Chapter II: Part I: , Clidastes, with Plates Ii-Vi

The group of extinct Cretaceous reptiles known as the Mosasaurs or Pythonomorpha was defined by Cope, “to whom Science is so largely indebted for its present knowledge of this interesting order of reptiles” (Marsh), in 1869.[4] Although some of the characters assigned by him to the order have since been shown to be inapplicable, and the group to have less value, yet his name, Pythonomorpha, has been generally retained. Lydekker and Zittel have assigned to the group a subordinal value, as has also Marsh, though under a different name. Owen rejected it entirely, and Baur, more recently,[5] has united it with the Varanidae to form a super-family, as follows:

Suborder Platynota.
Super-family Varanoidea.
Families Mosasauridae, Varanidae.
Super-family Helodermatoidea.
Family Helodermatidae.

The group, whatever may be its rank or position, includes, so far, the following genera: _Mosasaurus_ Conyb., _Liodon_ Owen, _Platecarpus_ Cope, _Clidastes_ Cope, _Baptosaurus_ Marsh, _Sironectes_ Cope, _Plioplatecarpus_ Dollo and _Hainosaurus_ Dollo. _Pterycollasaurus_ Dollo, founded upon _Mosasaurus maximilianus_ Goldf., is omitted as doubtful. All of these genera, save _Plioplatecarpus_ and _Hainosaurus_, have been recorded from North America, _Clidastes_, _Baptosaurus_ and _Sironectes_ being peculiar to this country. Of these latter three genera, however, _Clidastes_ alone is well known; but this genus is suspected by Lydekker of being the same as the imperfectly known European _Geosaurus_ Cuvier. Thus it seems that the genera, or at least the most of them, have a wide distribution; _Platecarpus_, in fact, is said to occur in New Zealand.

[4] Proc. Bost. Soc. Nat. Hist., p. 253.

[5] Science, xvi, p. 262, Nov. 7, 1890.

In America, members of the group have been discovered in the Cretaceous deposits of New Jersey, Alabama, North Carolina, the upper Missouri region, Nebraska, Kansas and New Mexico. Probably nineteen-twentieths of all the known specimens, however, have been obtained in western Kansas. The material now in the University Museum, all from Kansas, comprises several hundred specimens of these animals, including, probably, the best ones known. It is upon this material that the following preliminary studies are chiefly based.

The genus _Clidastes_, as first described by Cope, was based upon two dorsal vertebrae of _C. iguanavus_, the type species, from New Jersey. Shortly afterward, however, he gave a full and careful generic description, as derived from an unusually good specimen of an allied species, _C. propython_, from Alabama. Only a little later, Marsh described a genus, which he called _Edestosaurus_, from Kansas, but without giving any real, distinctive differences from _Clidastes_, following the very reprehensible practice of naming supposed new forms in the hopes that future distinctive characters might be found. The genus _Edestosaurus_ has been rejected by nearly all save the authors of the American text-books in Geology. It seems hardly necessary to point out the identity. The only distinctive character the author gave for his genus was the insertion of the pterygoid teeth, and even this character he modified later—“Palatine (sic) teeth more or less pleurodont.”[6]

[6] Amer. Journ. Sci. iii, June 1872.

This character, even were it real, is of very slight value; indeed it cannot be used to distinguish the species even.

_Clidastes_ is, without doubt, one of the most highly specialized genera in the group, and, what is very interesting, is one of the latest. It occurs in Kansas in the uppermost part of the Niobrara beds, in the horizon so markedly characterized by the toothed birds. Both _Platecarpus_ and _Liodon_ occur, though in diminished numbers, almost to the very lowest portion, but _Clidastes_ has never been found except towards the top. From measurements made the past season, the thickness of the beds in which these saurians occur cannot be less than six hundred feet.

The following species have been found in Kansas: none of them are known to occur elsewhere.

MOSASAURIDAE.

_Mosasauridae_ Conybeare, in Cuvier, Ossem. Foss., 2nd ed.,
p. 338, 1824.

_Clidastidae_ Cope, Extinct Batr. Rept. and Aves of N.
Amer., Trans. Amer. Phil. Soc. xiv, p. 50, 1870.

_Edestosauridae_ Marsh, Amer. Journ. Sci. xxi, p. 59, July
1878.

CLIDASTES.

? _Geosaurus_ Cuvier, Ossem. Foss. 2nd ed., 328, 1824,
(_fide_ Lydekker.)

_Clidastes_ Cope, Proc. Acad. Nat. Sci. Phil. 1868, p. 233;
Ext. Batr. etc., p. 21, 1870.

_Edestosaurus_ Marsh, Amer. Journ. Sci. i, p. 417, June,
1871.

=C. cineriarum.=

_Clidastes cineriarum_ Cope, Proc. Amer. Phil. Soc., 1870,
p. 583; Cret. Vert. etc. pp. 137, 266, pl. xxi, ff.
14-17; Bullet. U. S. Geol. Surv. Hayden, iii, p. 583.

=C. dispar.=

_Edestosaurus dispar_ Marsh, op. cit. i, p. 447, June 1871;
iii, pl. xi., June, 1872.

=C. velox.=

_Edestosaurus velox_ Marsh, Amer. Journ. Sci. i.
p. 450, June, 1871.

_Edestosaurus pumilus_ Marsh, ibid. p. 452.

? _Clidastes affinis_ Leidy, Proc. Acad. Nat. Sci., 1870,
p. 4; Rep. U. S. Geol. Surv., Hayden, vol. i, p.
283, 1873.

? _Edestosaurus dispar_ Marsh, op. cit. xix, pl. i, f. 1,
Jan., 1880.

=C. Wymani.=

_Clidastes Wymani_ Marsh, Amer. Journ. Sci. i, p. 451,
June, 1871; iii, p. 202, April, 1872.

_Edestosaurus Wymani_ Marsh, op. cit. iii, p. 464, June,
1872.

=C. tortor.=

_Edestosaurus tortor_ Cope, Proc. Amer. Phil. Soc. Dec.,
1871; Marsh, op. cit. iii, p. 464, June, 1872.

_Clidastes tortor_ Cope, Cret. Vert. Rep. U. S. Geol.
Surv., Hayden, vol. ii, pp. 48, 131, 265, pls. iv, f.
i; xiv, f. i; xvi, ff. 2, 3; xvii, f. 1; xix, ff. 1-10;
xxxvi, f. 3; xxxvii, f. 2; Bullet. U. S. Geol. Surv.
Hayden, vol. iii, p. 583.

=C. stenops.=

_Edestosaurus stenops_ Cope, Proc. Amer. Phil. Soc. p. 330,
1871: Marsh, Amer. Journ. Sci. iii, p. 464, June, 1872.

_Clidastes stenops_ Cope, Cret. Vert. etc. pp. 133, 266,
pls. xiv, ff. 4, 5; xvii, f. 7, 8; xviii, ff. 1-5;
xxxvi, f. 4; xxxvii, f. 3; xxxviii, f. 3.

=C. rex.=

_Edestosaurus rex_ Marsh, op. cit. iii, p. 462, pl. xxii, f. 1, June, 1872.

=C. planifrons.=

_Clidastes planifrons_ Cope, Bullet. U. S. Geol. Surv. No.
2, p. 31, 1874; Cret. Vert. etc. pp. 135, 265, pls.
xxii, xxiii.

=C. Westii.=

_C. Westii_ Williston, n. sp. infra.

CLIDASTES VELOX.

A remarkably complete specimen, referred with considerable certainty to this species, was obtained by ourselves in western Kansas, (Butte Creek) in the summer of 1891. A brief preliminary description of the specimen was given by the senior author in Science, December 8, 1891. A more complete description is here given, which, it is believed, will be of service. The specimen is an unusually perfect one, being very nearly complete, and, as now mounted, shows the bones nearly all in the position in which they were found. The vertebral column is continuous, except in one place, where the tail had been bent up over the back; and complete, save at the very tip of the tail. The skull is complete, or very nearly complete, and has been restored nearly to the condition in life. Figures have been made of this portion of the skeleton, and will be given in a future communication. At present, it may be mentioned that the lacrymals are small, roughly irregular bones, and pointed at either extremity. There are no indications of transverse bones, as there are none in any other skull in the collection.

Cervical vertebrae.

ATLAS. The intercentrum is a small bone with three sides of nearly equal extent. The two upper, articular surfaces are gently concave, and meet in a rounded margin; the inferior surface is convex, both antero-posteriorly and transversely, with a roughened prominence in the middle. The lateral pieces have indistinctly separated facets for articulation with the odontoid, the intercentrum and the occipital condyle. The rather short, flattened lamina extends upward, backward and inward, approaching, but not reaching its fellow of the opposite side; it is somewhat dilated distally. Directed outwards and forwards, there is a stout styliform process.

AXIS. The neural spine of the axis is elongated antero-posteriorly. It is thin on the anterior portion, but stouter and longer at the posterior part. The large, stout odontoid process is united suturally, as is also the well-developed atlantar hypapophysis, which forms the anterior, inferior portion of the bone. The diapophyses are the smallest of the costiferous series, with only a small articular facet for the rib. The ball is strongly and evenly convex, with its greater diameter transversely. The hypapophysis is the largest of the series; it is suturally united with the stout, exogenous process of the centrum, and projects downward and backward; its distal extremity is roughened for ligamentous attachments.

The third cervical vertebra shows a well-developed zygosphenal articulation, and stout articular processes. The transverse process is small, only a little larger than that of the axis, though, unlike that, it is strengthened by a ridge continued from the anterior zygapophyses. The hypapophysis is smaller than that of the axis, but, like that, is directed downward and backward. The spine may be distinguished from that of any other vertebra by its stout, trihedral shape; it is directed rather more obliquely backward than in the following vertebrae.

The fourth cervical vertebra differs from the third in having stouter transverse processes; in the hypapophysis being directed more nearly downward, and in its smaller size; and in the spine being flattened antero-posteriorly toward the base.

The fifth cervical vertebra differs from the fourth in the broader spine, in the stouter transverse processes, and the smaller hypapophysis.

In the sixth cervical vertebra, the hypapophysis is reduced to a small ossification, scarcely longer than broad, directed downward. The spine has reached nearly the full width of those of the following vertebrae, though somewhat stouter above. The transverse processes are yet stouter.

In the seventh, or last, cervical vertebra the hypapophysis is wanting, or very rudimentary. The under part of the centrum shows a rounded ridge or carina, with a slight projection corresponding to the hypapophysis.

MEASUREMENTS OF THE CERVICAL VERTEBRAE.

1. Antero-posterior diameter of intercentrum of atlas 14 millim.
Transverse diameter of intercentrum 25
Antero-posterior diameter of lateral piece 20
Vertical extent of articular surface 17
Extent of lateral piece 35
Width of lamina above 16
2. Length of axis 43
Transverse diameter of ball 18
Vertical diameter of ball 17
Expanse of transverse processes 28
Elevation of spine above floor of neural canal 34
Antero-posterior extent of spine 50
3. Length of third cervical vertebra 37
Height of spine above floor of neural canal 36
Depth of hypapophysis below floor of neural canal 34
4. Length of fourth cervical vertebra 37
Height of spine above floor of neural canal 39
Depth of hypapophysis below floor of neural canal 35
5. Length of fifth cervical vertebra 37
Height of spine above floor of neural canal 42
Depth of hypapophysis below floor of neural canal 33
Transverse diameter of ball 17
Vertical diameter of ball 18
6. Length of sixth cervical vertebra 37
Height of spine above floor of neural canal 42
Depth of hypapophysis below floor of neural canal 30
Width of spinous process 26
7. Length of seventh cervical vertebra 37
Height of spine above floor of neural canal 46
Transverse diameter of ball 19
Vertical diameter of ball 20
Width of spinous process 27

Dorsal vertebrae.

There are thirty-five vertebrae between the cervicals and the first non-rib-bearing vertebra, to which the pelvis was, evidently, attached. The distinction between the cervicals and thoracics cannot be made from any characters they possess, as the seventh vertebra does not bear a distinct hypapophysis. Neither can it be said with certainty from this specimen which is the first thoracic vertebra, as the cervical ribs had, unfortunately, been displaced in the collection and preparation of the specimen. In another specimen, referred to _C. pumilus_, and which, as will be seen later, cannot be specifically distinguished from the present species, short cervical ribs were found attached to six vertebrae posterior to the atlas. That the eighth vertebra is a thoracic one is shown by the relation of the ribs in this specimen. Posteriorly there is no distinction, also, between the true thoracic vertebrae and those of the lumbar region. All the vertebrae anterior to the pelvis bear ribs, and will all be considered as dorsal vertebrae, the true thoracic vertebrae being restricted to those of which the ribs are elongated, and, probably, connected with the sternum.

In the anterior vertebrae of the series, the centra are subcarinate below, the obtuse, rounded ridge becoming less and less apparent until no indications of the keel can be seen, before the middle of the series. The transverse processes are stoutest, with a more elongated, sigmoid articular surface, with little or no constriction, and projecting only slightly beyond the stout articulating processes, in the anterior vertebrae. In the tenth or eleventh, the articular surface has become markedly smaller, more vertical, and less sigmoid in outline. Thence to the last, the articular surface for the ribs remains nearly the same. The process itself, however, becomes gradually more prominent and constricted, as the zygapophyses becomes smaller. The spinous processes increase slightly in length and breadth, and are only slightly oblique throughout. In length, the centra increase gradually. The vertical diameter of the ball increases gradually, while the transverse diameter remains more nearly the same.

MEASUREMENTS OF THE DORSAL VERTEBRAE.

1. Length of centrum to rim of ball 38 millim.
Transverse diameter of ball 20
Vertical diameter of ball 19
Height of spine above floor of neural canal 48
Extent of articular surface of transverse process 30
Width of spine 28
4. Length of centrum to rim of ball 41
Transverse diameter of ball 20
Vertical diameter of ball 20
Height of spine above floor of neural canal 48
11. Length of centrum to rim of ball 41
Vertical diameter of ball 22
Extent of articular surface of transverse process 16
Width of spine 32
15. Length of centrum to rim of ball 41
Transverse diameter of ball 21
Vertical diameter of ball 24
20. Length of centrum to rim of ball 42
Vertical diameter of ball 25
Height of spine above floor of neural canal 58
24. Length to rim of ball 41
Transverse diameter of ball 22
Vertical diameter of ball 23
Height of spine 49
28. Length to rim of ball 40
Vertical diameter of ball 24
Transverse diameter of ball 23
Height of spine 54
32. Length to rim of ball 38
Vertical diameter of ball 25
Transverse diameter of ball 24
35. Length to rim of ball 37

Caudal vertebrae.

Immediately following the thirty-fifth rib-bearing vertebra there is an abrupt change, the tubercular process for the rib giving place to an elongated transverse process. From the position of the pelvis, it is evident that the ilia were attached to the first pair of these. Precisely this relation of pelvis to the vertebrae is found in such lizards as the Monitor and Iguana, and it is probable that such is the relation in all the Pythonomorpha. It will thus be seen that there are no distinctively lumbar vertebrae, if by such are meant free, non-costiferous, pre-sacral vertebrae. The vertebrae of these animals that have been so designated by writers are in reality basal caudal. A distinctive term for them—those with transverse, non-costiferous processes and without chevrons—is needed, and we propose, provisionally, the term _pygial_. There are seven in the present series, all characterized by elongated transverse processes, and not differing much from each other. The vertebrae lie in the matrix with the ventral aspect uppermost, concealing the spine and upper parts. The under surface is somewhat flattened, and, as in the preceding vertebrae, is gently concave antero-posteriorly. The transverse processes are elongate, stout towards the base, apparently all of nearly equal length, and directed gently backwards and downwards. In the anterior vertebrae the processes spring from near the front part: as the centra become shorter they arise from near the middle. In the last one of the series there are minute indications of chevrons.

MEASUREMENTS OF THE PYGIAL CAUDAL VERTEBRAE.

1. Length to rim of ball 36 millim.
Width of ball 25
Expanse of transverse processes 130
Width of transverse process near base 17
2. Length to rim of ball 33
3. Length to rim of ball 31
4. Length to rim of ball 29
5. Length to rim of ball 28
6. Length to rim of ball 27
Expanse of transverse processes 130
Width of ball 24
7. Length to rim of ball 27

The centra of those caudal vertebrae which have chevrons do not differ much in shape. They become less constricted, and, back of the middle of the series, are smoothly cylindrical in shape. The transverse processes decrease gradually in length, disappearing entirely in the twenty-fifth or twenty-sixth. The spinous processes are more or less incompletely preserved in the anterior vertebrae. They increase only gradually in length for the first twenty of the series, and are markedly oblique, with the posterior border stout, and the anterior border alate. With the twenty-sixth they begin to increase more rapidly in length, and have become more nearly vertical in position, and are thinner at each margin. In the thirty-fifth or thirty-sixth they attain their greatest length, and are here directed slightly forwards. Thence to the end of the tail, the length decreases gradually, and, in position, they are directed more and more obliquely backward. The chevrons are strongly oblique throughout the series and are firmly co-ossified with the centrum.

The tail, it is thus seen, has a broad, vertical, fin-like extremity, which, doubtless, aided much in the propulsion of the animal through the water.

There are sixty-seven vertebrae with chevrons present in the specimen, all continuous, except in one place. The last one is less than one-fourth of an inch in diameter, and shows that there had been yet another, possibly several more. Toward the base of the series the tail has been bent forwards over the back, and it is possible that, where the break occurs, there has been a vertebra lost. The measurements, however, do not seem to indicate any loss. The entire series of vertebrae was not less than sixty-eight, and probably not more than seventy, making for the entire vertebral series one hundred and seventeen to twenty.

MEASUREMENTS OF THE CHEVRON-BEARING CAUDAL VERTEBRAE.

1. Length to rim of ball 26 millim.
5. Length to rim of ball 24
Vertical diameter of ball 21
Transverse diameter of ball 24
10. Length to rim of ball 24
15. Length to rim of ball 24
Height of spine above floor of neural canal 40
Length of chevron 45
20. Length to rim of ball 23
Vertical diameter of ball 21
Transverse diameter of ball 22
25. Length to rim of ball 20
Height of spine 44
Width of spine at base 19
Width of spine at distal end 10
Length of chevron 85
Altitude of tail 112
30. Length to rim of ball 18
Vertical diameter of ball 17
Height of spine 57
Width of spine at base 19
Width of spine at distal end 9
Length of chevron 99
Altitude of tail 20
35. Length to rim of ball 16
Vertical diameter of ball 16
Height of spine 61
Length of chevron 97
Altitude of tail 122
40. Length to rim of ball 15
Vertical diameter of ball 15
Height of spine 54
Length of chevron 70
Altitude of tail 110
45. Length to rim of ball 14
Vertical diameter of ball 14
Height of spine 40
Length of spine 50
Length of chevron 58
Altitude of tail 93
50. Length to rim of ball 13
Length of spine 43
Length of chevron 55
Altitude of tail 73
55. Length to rim of ball 12
Length of spine 38
Length of chevron 42
Altitude of tail 63
60. Length to rim of ball 9
Length of spine 46
Length of chevron 25
Altitude of tail 50
66. Length to rim of ball 7
Length of chevron 10
Altitude of tail 20
67. Length 6

Ribs.

As has already been stated, the cervical ribs were displaced in the present specimen, and measurements of them cannot be given. In a smaller specimen, specifically indistinguishable from the present one, the entire cervical series is preserved with the ribs attached. The first, that articulating with the axis, is very short. The following ones are stouter, but increase only moderately in length, that of the sixth measuring only thirty-five millimeters, while that of the seventh is but a little longer. In the specimen of _C. velox_ described, there is a detached cervical rib sixty-five millimeters in length; it probably belongs with the seventh.

The thoracic ribs are simple, somewhat flattened rods, moderately expanded at the proximal end. The greatest convexity is shown about the middle of the series, where the versedsine of the curvature is forty millimeters, the chord being one hundred and sixty. Posteriorly, the short ribs are only gently curved.

Lying by the side of the vertebral column, and between the ribs, as they have been pressed down, are a number of flattened, soft, punctulate bones, which are evidently the costal cartilages. Posteriorly four rows of them are seen, lying closely side by side, some of them eight or ten inches in length. The sternum, composed of the same material, has been so crushed and crumpled that its shape cannot be made out. The whole structure here, whether of ribs, cartilages or sternum, reminds one very strongly of such lizards as the Iguana or Monitor. There is no indication, however, in any specimen, of an episternum.

MEASUREMENTS OF RIBS.

Length, first thoracic rib, (chord) 200 millim.
Length, eleventh thoracic rib, (chord) 145
Length, thirteenth dorsal rib 68
Length, eighteenth dorsal rib 64
Length, thirty-fourth dorsal rib 52

The lengths of the different regions, as they lie in their natural relations, are as follows:

Skull 0.420 meters.
Neck 0.225
Trunk 1.360
Tail 1.460
Total 3.465 11 ft. 7 in.

The measurements of an excellent specimen of _C. tortor_ are as follows:

Skull 0.630 meters.
Neck 0.360
Trunk, (thirty-three vertebrae preserved) 2.370

A very complete specimen of a _Liodon_ in the Museum, in which the _complete_ vertebral column is present, numbering one hundred and seventeen vertebrae, gives the following measurements. The skull is complete, save the most anterior portion.

Skull (approximated within narrow limits) 0.700 meters.
Neck 0.430
Trunk 1.760
Tail 3.420
Total 6.310 20 ft. 8 in.

The vertebral series in this specimen is composed of seven cervicals, twenty-three dorsals, seven pygials, and eighty chevron-caudals.

The relative proportions of the different regions in the two genera, as shown by the two specimens of _Clidastes_ and _Liodon_, may be represented as follows. The first column is for _Clidastes_.

Skull 12.1 11.1
Neck 6.5 6.8
Trunk 39.2 28.0
Tail 42.3 54.1

Limbs.

The figures in plates II and III will give a sufficiently good idea of the limbs in this specimen. They are figured as they were lying, showing the outer sides of the coracoid, scapula and pelvic bones, and the palmar or plantar surface of the remaining bones.

Coracoid.

It will be observed in plates II and IV that there are two very different types of coracoid, one with a deep emargination, the other without the slightest indication of such. The same non-emarginate form occurs in _C. tortor_, as specimens in our Museum show, in _C. propython_ Cope (Ext. Batr. etc. pl. xii, f. 16,) and in _C. dispar_, as figured by Marsh[7], and as stated by him in the same paper (“There is certainly no emargination in the coracoid of _Clidastes_, _Edestosaurus_ and _Baptosaurus_, as specimens in the Yale Museum conclusively prove.”) It is true that Marsh in a later paper[8] figured a specimen with emarginate coracoid under the name of _Edestosaurus dispar_, but it is certain that his identification of his own species was wrong, as will be seen by comparing his figures. From the senior author’s memory of the specimen with the emarginate coracoid figured, and from the figure itself he feels confident that the second specimen is _C. velox_.

[7] Amer. Journ. Sci. iii, pl. xi, f. 1, June, 1872.

[8] Amer. Journ. Sci. xix, pl. i, fig. 1, Jan., 1880.

That the emargination was overlooked by the author seems strange, as in the same paper in which this figure is given occurs the description of _Holosaurus, founded upon that very character_. If the emargination is sufficiently important to base a genus in the one case, then it should be in the other, and the character could not be applied to _Edestosaurus_, based upon characters which it hardly seems possible that the author himself could seriously consider, for _E. dispar_ was the type of _Edestosaurus_.

It will be observed, further, that the figured coracoids differ very materially in size, those with the emargination pertaining to a small species, while _C. dispar_ is one of the largest. In our Museum there are three specimens with the emarginate coracoid, all of them small or very small, the described specimen of _C. velox_ being the largest.

The point of chief interest in this relation is the value that can be given to this character. Is it individual, specific or generic? Marsh has called it generic, but we think an examination of the two very complete specimens of _C. tortor_ and _C. velox_ in our Museum will convince any unprejudiced student that he is in error.

A comparison of the figures herewith given of the paddles will show their great resemblance, and these two forms of paddles have been figured because the species are the most unlike of any that we know in the genus. As all the small specimens seem to possess this character, and as they cannot be called immature specimens, we believe the character is a specific one. As Marsh says, typically both _Clidastes_ and _Edestosaurus_ have a non-emarginate coracoid, so that neither name could apply to the emarginate form, were it generically distinct.

Our Museum also contains both forms of the coracoid pertaining to the genus _Platecarpus_, of which _Holosaurus_ is a synonym.

While studying the specimen above described, a striking similarity was observed to several other specimens already determined with confidence as _C. pumilus_ Marsh. A more careful comparison failed to bring out any real differences beyond size, and even this was shown to be very inconstant.

The following comparison of the descriptions given by Marsh will be of interest.

_C. pumilus._

TEETH. Nearly round at base somewhat curved
and with smooth enamel.

QUADRATE. The rugose knob near the distal
end of the quadrate is similar to that in _C.
Wymani_ (just below the posterior superior process
is a prominent rugose knob with a deep pit under
it), but has no articular pit under it. The hook
is comparatively short and has a free compressed
extremity. The articular margin is not deflected
toward the meatus.

CERVICAL VERTEBRAE. Articular face nearly
vertical, and having a broad transverse outline with
faint superior emargination. The hypapophysis stout
and transversely triangular.

_C. velox._

Premaxillary and maxillary teeth smooth and
subcompressed.

The great ala less curved than in _E. dispar_, concave
transversely on both surfaces. The alar process has
its articular process very narrow in its extension
over the great ala. No notch in posterior margin of
external angle. On the ridge below the angle and
nearly opposite the meatal pit is a strong rugosity
which is rudimentary or wanting in _C. dispar_. The
posterior margin of the hook is only a narrow tongue
projecting towards the meatal pit, instead of a broad
articular surface.

Articular face transverse.

The description, otherwise, shows no discrepancies of importance. The chief difference given by the author is the size, and this character we think our specimens show to be of little specific value. “It is a question of some importance how far difference in size among the Mosasauroids may be a test of difference in species. Among the numerous remains of these animals which have been discovered I have never yet observed any which presented any evidence relative to age. * * * In this view of the case, some of the many described species of Mosasauroids may have been founded on different sizes of the same.”[9]

[9] Leidy, Rep. U. S. Geol. Surv. Hayden, vol. i, p. 284.

The length of the cervical vertebrae in the specimen above described is thirty-seven or thirty-eight millimeters. The cervical vertebrae in two specimens referred to _C. pumilus_ have lengths respectively of twenty-two and thirty millimeters. In the type specimen of _C. velox_ they must have had a length of at least forty-two millimeters.

It thus appears that, between the smallest specimen, which, in life, could have hardly exceeded eight feet in length, our specimens, indistinguishable anatomically, represent forms of ten and twelve feet, while the type itself was about fifteen feet in length.

Of the material originally referred to _C. pumilus_, there are in the collection five or more specimens, which, altogether, furnish nearly every part of the skeleton. They present no tangible differences from the skeleton of _C. velox_ described above. There can be, hence, little or no doubt but that the name _C. pumilus_ is a synonym.

It is hardly possible to say with certainty that _C. affinis_ Leidy is or is not the same as _C. velox_, but, so far as the description goes, we can find few differences. The type is of about the same size as the type of _C. velox_, and the figures agree well with the bones of the skeleton described. Although the description was not published till 1873, the author makes no mention of the species of Marsh’s. Leidy describes the back teeth as having the enamel strongly striated, with the surface presenting evidences of subdivision into narrow planes. In this respect, only, it disagrees with the specimen.

_Plioplatecarpus_ Dollo is described by its author as having a sacrum of two conjoined vertebrae,[10] by reason of which it is placed in a separate family from the rest of the _Pythonomorpha_. It may be presumptuous to express a doubt of the genuineness of the sacrum, and yet, save from the fact that the author found two specimens quite alike, one might doubt it strongly. It is not very rare that two, or even three vertebrae are found united from injury in these animals, and such would readily account for the consolidation as figured and described by Dollo, except for the coincidence of the second specimen. A stronger reason for doubt is the statement that the consolidated vertebrae belong to the posterior “lumbar” region, and that the last vertebrae had small tubercles indicative of chevrons. In the reptiles which we have examined, the chevrons do not begin immediately behind the pelvis, but are separated by a longer or shorter region in which the vertebrae bear elongated diapophyses alone. If the conjoined vertebrae figured by Dollo are in reality sacral, it would appear that the animal is an exception to _Clidastes_ and such lizards as we have examined. Furthermore, the pelvis must have been of a different structure from that in the Kansas genera of the Pythonomorpha, for, in these, it is evident that the ilium had an oblique position, and could have been attached to but a single diapophysis.

[10] Bull. Su. Mus. Roy. S. Hist. Nat. d. Belg. i, p. 8, 1882.

CLIDASTES WESTII, N. SP.

A specimen of much interest in the University collection differs so markedly from the other forms represented by specimens, as also from the descriptions of the known species, that we are constrained to regard it as new. It was collected by Mr. C. H. Sternberg from the uppermost of the Niobrara beds, in the vicinity of the old town of Sheridan. The character of the associated invertebrate fossils seems to indicate a different geological horizon, either the Fox Hills group, or transition beds to that group. The specimen consists of a complete lower jaw, quadrate, portions of the skull, the larger part of the vertebral column, and the incomplete hind and fore paddles. The vertebrae preserved are in two series, the one, numbering thirty-three, continuous with the skull; the other, sixty-three in number, all chevron caudals. The terminal caudals preserved indicate that there were several more in life, perhaps five or ten; the first of the series was evidently among the first of those which bore chevrons. Altogether the tail may have had seventy-five chevron caudals. The lengths of the two series are respectively seventy-one and seventy-two inches. Assuming that there was the same number of precaudal vertebrae as in _C. velox_, the entire vertebral column would have measured in life fifteen feet and four inches. The lower jaw shows the skull to have been very nearly twenty-four inches in length, making, for the animal when alive, a length of seventeen and one-half feet. This is one of the largest species, and it is interesting to observe that the real size here, as usually elsewhere among fossil vertebrates, is less than supposed. It is doubtful whether there is a _Clidastes_ known that exceeded twenty feet in length.

While the skeleton was only about one half longer than the specimen of _C. velox_ described in the foregoing pages, or of about the same length as a very complete specimen of _C. tortor_ in the museum, the proportions of the animal were very much stouter. The figures given in plate VI of the twenty-fifth, or eighteenth dorsal, vertebra will show the relations between length and breadth: it is upon these remarkably stout proportions, and the shape of the articular faces, as indicated by the figures and by the measurements appended, that the species is chiefly based. The articular surfaces of the basal caudal vertebrae are remarkably triangular in shape, with the angles rounded, and the sides of nearly equal length. This triangular shape is persistent for the first twenty of the series as they are preserved. The paddles, as shown in plates IV and V, show much stouter proportions than in either _C. velox_ or _C. tortor_.

The species comes nearest to _C. stenops_ Cope, but it seems hardly the same. It is, also, evidently allied to _C. dispar_ Marsh. From these and other described species, the following, extracted from the original descriptions, will serve to show the differences, in comparison with the specimen of _C. Westii_.

=C. dispar.=

The articular faces in the cervicals are a broad transverse oval, faintly emarginated above for the neural canal. In the dorsals and lumbars the cup continues transverse, and the emargination is deeper, but in the anterior caudals the outline becomes a vertical oval. There appears to have been thirteen mandibular teeth.

Length of axis with odontoid process 32 lines 100
Width between diapophyses 26.8 103
Length from edge of cup to end of ball in
eleventh vertebra 25 100
Width of ball 14 56
Depth of ball 12 43

=C. Wymani.=

In the cervical vertebrae, the outline of the articular faces is transversely cordate. The centra of the anterior dorsals are elongate, and much constricted behind the diapophyses. In the anterior caudals, the articular faces are a broad vertical oval.

Length of axis with odontoid process 19 lines 100
Width between diapophyses 17 89.4
Width of ball 8 42.1
Depth of ball 7 36.7
Length of sixth cervical, without ball 13 100
Width of cup 9 69.1

=C. rex.=

The cervical vertebrae have very broad, transversely oval faces, with indications of emargination. The dorsals are elongated, with transverse faces, and a distinct superior excavation for neural canal. The articular ends of the anterior caudals are vertically oval.

Length of posterior cervical vertebrae 44 mm 100
Vertical diameter of ball 24 54.5
Transverse diameter 29.5 67
Length of a dorsal vertebra 52

=C. stenops.=

The anterior caudals possess wide diapophyses. Their articular faces are a vertical oval, a little contracted above, sometimes a straight outline. They present a peculiarly elongate form.

Length of axis (alone) 60 mm 100
Vertical diameter of ball 27 45
Transverse diameter of ball 27 45
Length of the mandible 720 100
Depth at coronoid process 150 20.9

MEASUREMENTS OF CLIDASTES WESTII.

Length of dentary 400 millim.
Depth opposite the first tooth 20
Depth opposite last tooth 62
Entire extent of mandible 630
Greatest depth at coronoid process 95
2. Length of axis with odontoid process 80
Length of axis without odontoid process 70
Vertical diameter of ball 24
Transverse diameter of ball 33
4. Length of fourth cervical vertebra to rim of ball 49
Expanse of diapophyses 82
5. Length of fifth cervical to rim of ball 49
Transverse diameter of ball 35
Vertical diameter of ball 28
Expanse of diapophyses 90
8. Length of eighth vertebra to rim of ball 53
Expanse of diapophyses 90
14. Length to rim of ball 54
Transverse diameter of ball 40
Vertical diameter of ball 33
Expanse of diapophyses 100
18. Length to rim of ball 50
Transverse diameter of ball 40
Vertical diameter of ball 36
Expanse of diapophyses 100
23. Length to rim of ball 50
Transverse diameter of ball 41
Expanse of diapophyses 100
25. Length to rim of ball 52
Transverse diameter of ball 43
Vertical diameter of ball 43
Expanse of diapophyses 100
30. Length to rim of ball 54
Transverse diameter of ball 46

This species is named in memory of Judge E. P. West, lately deceased, to whom our Museum owes so much for his long, diligent and faithful labors in the collection and preparation of the geological material.

* * * * *

ERRATUM: P. 17, line 15, for “_Edestosaurus_,” read _Clidastes_, and in next line, strike out “Proc. Acad.” etc.

Notes and Descriptions of Syrphidae.

BY W. A. SNOW.

WITH PLATE VII.

Among the insects obtained by Prof. F. H. Snow in a recent trip to Colorado, is an excellent representative collection of the Diptera. The material for the following notes on Syrphidae is chiefly drawn from this collection. That such a collection affords so many points of interest in this, one of the best studied families of North American Diptera, is an evidence of the rich field that is presented by this important and little-studied order of insects.

CALLICERA.

_Callicera_ Panzer, Fauna Germanica, 1806.

_Callicera_ is a small genus hitherto supposed to be peculiar to Europe. The species are found in the high mountains, where the males are often taken while hovering in the air. The present collection includes numerous specimens of a species taken near the summit of Mt. Deception, in Manitou Park, Colorado, at an altitude of nine thousand feet.

The occurrence of members of this genus in the western part of the United States is a fact of especial interest and further substantiates the rule that American forms common to Europe are more apt to occur in the western regions. _Arctophila flagrans_ Osten Sacken, is a case precisely similar to the present one, belonging as it does to a small European genus of mountain flies, and described from Colorado.

As the genus is a new one to our fauna, I here give an amended transcription of the generic characters from Schiner’s Fauna Austriaca, to include the new species, which differs only in unimportant details.

=Callicera.=

Rather large, stout, green or black species with metallic lustre and abundant, long pile. Head hemispherical, somewhat broader than the thorax. Antennae porrect, longer than the head, somewhat remote at their base, inserted upon a protuberance of the front; first joint sometimes elongate; second joint shorter than, or as long as, the first joint; third joint one to three times the length of the first two joints taken together, with a short, terminal style. Face broad, under the antennae concave in profile; an obtuse tubercle below the middle; on the sides thickly covered with pile. Proboscis rather prominent, with broad labella. Eyes hairy, holoptic in the male. Abdomen elliptical, as long or longer than the thorax. Legs moderately strong. Third longitudinal vein straight, first posterior cell distally short petiolate; marginal cell open; cross-vein situated near the middle of the discal cell, oblique.

=Callicera montensis, n. sp.=, Plate vii, f. 4.

MALE. Black, densely golden red pilose. Frontal triangle, face and cheeks deep black, shining, covered thickly with black pile, save a median facial stripe. Antennae black, basal third of third joint on the under side red; first joint short; second joint not more than half as long as the first; third joint three times as long as the first and second joints taken together; gradually broadened for a third of its length, and then attenuated; style white. Eyes thickly clothed with golden pile. Thorax and abdomen covered everywhere with long golden red pile. Legs black; tarsal joints below and at their articulations reddish. Wings nearly hyaline, brownish on the anterior basal portion; stigma yellow.

Length 11 millimeters. Three specimens, Colorado.

The genus may be distinguished from _Pelecocera_, in Williston’s dichotomic table of the genera of North American Syrphidae, by the pilose eyes.

=Microdon megalogaster, n. sp.=, Plate vii, f. 1.

MALE. Large, yellowish pilose species, in shape globose. Antennae reddish black, the first joint about as long as the following two together; second joint not one-third as long as the third. Face dark metallic green, shining, thickly covered with golden yellow pile. Front black, with similar pile, narrowed in the middle. Eyes bare. Thorax and scutellum deep metallic green, with long, thick, golden pile; scutellum gently emarginate, the small obtuse tubercles approximate. Abdomen short and broad, black, moderately shining; first two segments and the hypopygium somewhat green; pile at base yellow, elsewhere short, black. Legs black, with black pile; front tibiae and their metatarsi, on the inner side, with short golden pile; hind metatarsi incrassate and longer than the three following joints taken together. Wings uniformly subinfuscate; veins at the outer part of the first posterior and discal cells sinuous and rounded.

Length 12 millimeters. One specimen.

=Chrysotoxum derivatum= Walker.

Eight specimens from Colorado, which vary not a little from each other and from Williston’s description. They seem to belong here, however, better than elsewhere. In one specimen, the second joint of the antennae is shorter than the first, and only one-fourth the length of the third. In five examples the second abdominal cross-band is not interrupted; in the others it is distinctly parted. In two, the third band does not reach the yellow of the broad hind margin; in two others it barely touches it; in five, the two bands broadly coalesce. The yellow of the fifth segment, in four specimens, incloses a black, inverted V; in two others an inverted Y.

=Paragus bicolor= Fabr.

Three specimens, Colorado. These may be located under Schiner’s variety _taeniatus_.

=Melanostoma stegnum= Say.

_Syrphus stegnus_ Say, Journ. Acad. Phil. vi, p. 163.
_Melanostoma tigrina_ Osten Sacken, Western Diptera, p. 323.
_Melanostoma stegnum_ Williston, Biol. Centr.-Amer. Diptera,
iii, p. 10.

Eleven specimens, Colorado, which answer well to the descriptions. The metallic band of the fourth abdominal segment is sometimes interrupted, and there is usually a triangular opaque black spot near the anterior border of the fifth segment. “The female, hitherto unknown, has the front broad above, pollinose, except on the upper part, and with black pile; the thorax more shining metallic blue; the tibiae yellow, and on the third and fourth abdominal segments there is a narrow shining stripe, bisecting the black, as in the fourth segment of the male. The male has some long black hairs on the outer side of the front and middle tibiae, which are inconspicuous in the female. It is evident, from the lighter color of the tibiae, that Say’s specimens were females.” Williston, l. c.

=Melanostoma mellinum= Linne.

A single female specimen from Manitou Park.

=Melanostoma, n. sp.=?

MALE. Face and front dark metallic blue, shining, thinly covered with light-colored pollen; tubercle and epistoma black, shining, the former small. Antennae black, third joint yellowish red below, oblong. Pile of frontal and vertical triangles dusky. Thorax bronze-black, shining, sometimes bluish black, the pubescence white. Halteres yellowish. Abdomen long and narrow, with almost parallel sides; first segment metallic blue, shining; second segment opaque, or subopaque, black, with a light metallescent scallop on the sides, reaching to the distal third of the segment; third and fourth segments similar, marked anteriorly by a wide, interrupted, or subinterrupted blue fascia, deeply and widely emarginated, or concave behind; hind border of the third, and sometimes of the second segment, narrowly brown; fifth segment and the hypopygium metallic bluish green; sides of the abdomen with silvery white pile, longest and thickest at the base; the blue marking are whitish pruinose. Femora, except the tip, a broad ring on the tibiae, and the four posterior tarsi, black; elsewhere brownish or yellowish. Wings hyaline, stigma yellowish.

Length 7-8 millimeters.

=Eupeodes volucris=, Osten Sacken.

Numerous specimens, Colorado.

=Syrphus arcuatus= Fallen.

Four specimens, Colorado. These specimens vary not a little from each other, and somewhat from the descriptions. One female is very small, not over seven millimeters in length, and with the spots on the third and fourth abdominal segments hardly oblique. One male has the hind femora black as far as the tip, while in three females the black does not extend beyond the middle.

=Syrphus disjectus= Williston.

A single female specimen, from Colorado, agrees well with the description drawn from males. The pile of the thorax is more whitish than orange-yellow, and there are light colored lateral margins on the anterior part of the thorax.

=Syrphus ruficauda, n. sp.=, Plate vii, f. 3.

MALE. Eyes bare. Face greenish yellow on the sides, yellow in the middle; a rather broad black line marks the border of the mouth and is lost in the black of the cheeks. Frontal triangle yellow, with long black pile. Antennae dark brown, more or less reddish below. Pile of occiput light yellow. Dorsum of thorax deep metallic green, the scutellum olivaceous yellow; both with light yellow pile. First segment of the abdomen shining black; second segment opaque black, with the lateral margins and hind border shining, and with a broad, yellow, interrupted band, not reaching the lateral margins; third segment similar, but with the yellow band somewhat wider, interrupted or subinterrupted and slightly bilaterally oblique; fourth and fifth segments orange-red, the sides narrowly black; the fourth segment shows indistinctly a broad interrupted band of a somewhat lighter color, corresponding to the yellow bands of the preceding segments. Legs light brown; basal third of the front and middle femora and basal half of the hind femora black. Wings hyaline, stigma yellowish.

FEMALE. Head wanting. Thorax purplish brown. The yellow band on the second abdominal segment narrower, the second band straight, narrower and interrupted. Legs light brown, except the proximal end of the femora, which is black.

Length 9 millimeters. Three males and one female, Colorado.

=Syrphus pauxillus= Williston.

Two specimens from Colorado undoubtedly come here. The species was described from a single male specimen. A female specimen offers the following differences or additions: Length nine millimeters, mesonotum more greenish black or bronze, the pile obscure whitish; fifth abdominal segment without yellow spots on the anterior angles; legs yellow, with the basal half of the front and middle femora, the hind femora except the tip, a broad band on the hind tibiae, and the hind tarsi, black.

=Syrphus ribesii= Linne.

Five specimens, Colorado.

=Syrphus americanus= Wiedemann.

Numerous specimens, Colorado.

=Syrphus umbellatarum= Schiner.

Five female specimens, Colorado. The only western locality heretofore given is Arizona (Williston).

=Allograpta obliqua= Say.

Five specimens, Colorado.

=Mesogramma marginatum= Say.

Numerous specimens from Colorado, showing very great variation.

=Sphaerophoria cylindrica= Say.

Twenty specimens, Colorado. I think the specimens belong here, though a positive identification is hardly possible at present.

=Rhingia nasica= Say.

One specimen, Colorado. This is the first time that this species has been recorded from beyond the Mississippi.

=Copestylum marginatum= Say.

Two specimens, Colorado, representing the extremes of variation in the species. The male corresponds to _C. lentum_ Williston. Specimens of this species were bred from _Opuntia missouriensis_, in company with others of _Volucella fasciata_ Macq.

=Sericomyia militaris= Walker.

Sixteen specimens from Minnesota and Colorado vary in the markings of the second abdominal segment, and in the color of the legs. Some have no spots at all on the second segment; in others the two yellow dots are conspicuous, approaching, in size and shape, the markings of the third segment. The tibiae vary from light yellow to reddish brown.

=Brachyopa cynops, n. sp.=, plate vii, f. 2.

Head light yellowish brown, largely concealed beneath light glistening pollen; the shining ground color shows just above the antennae and in a stripe on the cheeks, extending from the eye to the mouth opening. Antennae wanting. Dorsum of thorax brown, covered with grayish pollen; anteriorly with two approximated, linear, blackish stripes; laterally with a broad, interrupted stripe. Scutellum light brown, with yellowish pollen. Abdomen but little longer than broad; yellowish gray pollinose; second segment with a circular brown spot in the anterior corners; the two following segments are marked with corresponding elliptical spots, and, in the middle of the anterior border with a triangular spot; on the fifth segment are two small round spots. Legs uniformly reddish brown, with light colored pollen and short whitish pile. Wing hyaline, distinctly clouded at anterior cross-vein, on the veins at the anterior outer corner of the discal cell and on the ultimate section of the fourth vein; posterior cross-vein about as long as the penultimate section of the fourth vein, the included angle obtuse.

Length 5 millimeters. One specimen, Colorado.

=Eristalis latifrons= Loew.

Numerous specimens, Colorado. The commonest Syrphid of the mountain meadows. Some specimens have very indistinct brownish spots on the second abdominal segment, and, when this is the case, the middle of the wing generally shows a brown spot, and brown clouds along the anterior veins between the spot and the base of the wing.

=Eristalis brousi= Williston.

One male specimen, Colorado.

=Helophilus latifrons= Loew.

Numerous specimens, Colorado.

=Xylota flavitibia= Bigot.

Eight specimens, Colorado. The glistening pile of the face and front varies from white to a golden yellow. On the dorsum of the thorax purplish stripes are distinctly visible. The fourth segment of the male abdomen is often red, as in the female abdomen.

=Syritta pipiens= Linne.

Eight specimens, Colorado.

=Criorrhina umbratilis= Williston.

A single, male specimen, collected by Mr. W. J. Coleman, at Lawrence, and agreeing exactly with the description. The only other known specimen of this species is the type, at Washington, from Connecticut.

=Spilomyia quadrifasciata= Say.

Seven specimens, Lawrence, Kansas, (F. H. Snow and E. S. Tucker). The species has not hitherto been recorded west of New York.

Notes on Melitera Dentata Grote.

BY VERNON L. KELLOGG.

WITH PLATE VIII.

At the meeting of the Entomological Club of the A. A. A. S., held in August, 1891, at Washington, Dr. Riley called attention to the habits of _Melitera prodenialis_ Walker. The larvae burrow into and feed upon the fleshy leaves of the prickly pear, _Opuntia_. Dr. Riley’s specimens came from Florida. Prof. J. B. Smith has recently bred the moth from the prickly pear in New Jersey. His notes were presented at the same meeting of the Club, and the brief references to the interesting notes of Doctors Riley and Smith, made in the Canadian Entomologist (v. xxiii, num. 11, pp. 242 and 256), suggest the presentation of the following notes on _Melitera dentata_ Grote, the western species of this Phycitid genus.

Chancellor F. H. Snow, of this University, while investigating a grasshopper “outbreak” (_Dissosteira longipennis_) in eastern Colorado in July, 1891, noted the withered and dying condition of many leaves of the common prickly pear cactus (_Opuntia missouriensis_), and on examining the leaves found in them certain large, naked, bluish larvae. The larvae were imbedded in the fleshy leaves, eating away the soft inner tissue. The hollowed-out spaces were nearly filled with irregularly spherical, yellowish, translucent casts. The attacked leaves were withered and brown without. Prof. Snow took a few leaves and larvae on July 16, near Arriba, Colorado, and brought them to the laboratory.

The larvae were put into breeding-cage on July 18. On July 28 one larva had spun up and pupated in a corner of the cage behind a small porcelain dish. Another had made a cocoon in a broken, empty pupa-case of _Eacles imperialis_, but died before pupating. On August —— the adults appeared, and have been determined by Prof. J. B. Smith as _M. dentata_, Grote. As I am aware of no description of the earlier stages of this species, I record the following notes of description:

EGG. About 1-1.2 millimeters in diameter, surface with broad, meridian-like furrows from one pole for about one-third of the distance to the other pole. Color, creamy white.

LARVA. Food plant, _Opuntia missouriensis_, prickly pear cactus, burrowing into the fleshy leaves and eating the soft, succulent, inner tissues. Length, 40 millimeters. Five pairs of prolegs. Color, one specimen, ultramarine blue; skin, semi-transparent and shining anteriorly, dead blue on dorsum; second specimen, buffy with a bluish suffusion, blue between segments, prolegs bluish, and last abdominal segment blue, especially below; skin more opaque than in first specimen. No pronounced markings of skin; spiracles shining black and present on first thoracic and first to tenth abdominal segments. Head flattened, slightly narrower than first thoracic segment, umber. Prothoracic shield well marked, brownish black; anal shield, smoky brownish. Clothing, limited to tubercled hairs sparsely distributed as follows: a subdorsal line of small tubercles, two tubercles to a segment, each tubercle bearing three short, fine hairs; a supra-stigmatic line, one tubercle to each segment, each tubercle bearing three to four fine hairs; a similar infra-stigmatic line; a sub-ventral line of tubercles, bearing usually four fine hairs, the tubercles of the three thoracic segments in this line situated at base of legs outside, and similarly as to the prolegs on the third to sixth abdominal segments. The tubercles in all the lines are faintly smoky. The larva is rather heavy, and rotund in form, tapering toward both head and posterior segment. It moves with a lumbering gait, but rather rapidly.

CHRYSALIS. Length, 20 millimeters; in cocoon of silk, loosely covered with small dirt-masses. As made in the breeding cage the cocoons were above ground, but concealed under or in available objects.

ADULT. The adults obtained from the breeding cage, (there are no others in our collection), are easily distinguished from _prodenialis_ Wlk., by the much stronger dentations of the outer line of the primaries. Prof. Smith kindly sent a specimen of _prodenialis_ taken at Ocean Grove, New Jersey, for comparison. The row of marginal black spots on the primaries which Hulst (Tran. Am. Ent. Soc., v. xvii, p. 172) mentions as distinctive of dentata is as pronounced in Prof. Smith’s specimen of _prodenialis_ as in our _dentata_. The much lighter color of the primaries, head and thorax in dentata as mentioned by Hulst is characteristic. An interesting feature in the venation of the hind wings in our bred specimens of _dentata_ is the considerable coalescence of the sub-costal and costal veins. Vein five is wanting, as mentioned by Hulst. In addition, there is further departure from a normal venation, in that vein seven after rising with six from its stem, (Hulst says: “Six short stemmed with seven”), coalesces for a short distance with eight and then runs free to the margin. Behind the forking of seven and six the stem (remnant of sub-costal) unites with the costal, and its basal portion is wholly merged with the forward vein. This partial disappearance of the sub-costal seems to be shared by _prodenialis_ and is probably characteristic of the genus.

Prof. Smith, as recorded in the Canadian Naturalist, v. viii, p. 242, (1891), bred several specimens of _Volucella fasciata_, a Syrphid fly, from the same prickly pear leaves in which the _Melitera_ larvae were living. It is interesting to note that pupariae and later, adults of _Volucella fasciata_ and _Copestylum marginatum_, a closely allied Syrphid, were noted in the Opuntia leaves from which _M. dentata_ was bred. (See note by Dr. Williston, Entomological News, v. ii, p. 165, 1891).

Diptera Brasiliana.

BY S. W. WILLISTON.