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(4th Group.)
Gen. Papilio Linné, 1758.

Type : P. machaon. Vein iii, arises out of radius more or less exactly opposite to the point of junction with discal cross-vein. Cells subequal. Vein iii, of primaries free to costa. Internal vein of hind wings inwardly curved, attaining the margin just before the short excision at anal angle. Cubital cross-vein joins with vein vii.

Except podalirius, the types of the genera arranged under this rubric agree in main features, while differing in small details which it is optional to consider as of generic value. In machaon the humeral cell of hind wings is small and narrow. The præcostal spur has a lateral extension. There is a moderate, narrow tail, not spatulate.

(5th Group.)
Gen. Trogonoptera Ripp., 1890.

Type : T. brookeana. Vein iii, arises just before the point of junction of cross-vein with radius. Cubital cross-vein not attaining vein vii. Fore wings long and narrow, pointed, entire. Hind wings reduced, rounded, tailless. Internal margin full, the vein straight, continuous. From the characters of the radius this genus is nearer to Papilio than to Ornithoptera. It is remarkable how persistent the neurational features are in the group of Papilio, and especially that vein iii, is so immovable in its position nearly exactly opposite the cross-vein. It must be therefore considered an important feature that this vein arises much beyond the cross-vein in Leptocircus, and before it in Ornithoptera. In Trogonoptera brookeana it has not quite attained the Papilionid position, but it has decidedly abandoned that of Ornithoptera. The structure of the hind wings resembles that of the latter genus.

(6th Group.)
Gen. Ornithoptera Boisduval, 1832.

Type: 0. priamus. Vein iii, arises out of radius above cell and well before the point of junction of cross-vein. Discal cells subequal. Vein iii, free to costa. Internal vein of hind wings reaching anal angle; no anal excision.

The comparative characters are those of generalization, so that Ornithoptera presents features which the rest of the Papilionides have probably abandoned. In the same way I assume that the species of Eurymus (Colias Auct.) have passed through a Meganostoma stage, and the entire extant Pieridæ an Anthocharis stage, in which latter the Radius was five-branched and generalized. There is a strangeness about Ornithoptera, suggesting a separate origin. This disappears with the higher forms of the Papilionides, which have come to look much like other butterflies. The remaining generic types may be now gone over in review.

As far as possible I take the generic titles in their chronological order.

(2d Group.) Zetides sarpedon.

Agrees with Tilaides, except that the secondaries are bluntly produced inferiorly and are without a tail. Vein iv, lies somewhat nearer iv, at base. In both genera the excision at anal angle is long, owing to the produced wing, but vein vii is not relatively shorter, as in Eurycus (3d Group). Zetides appears more specialized than Idaides. The differences are small, but may be considered as of generic importance. Arisbe similis.

Agrees with Idaides, except that the secondaries are not produced inferiorly ; the outer margin is rounded, without salient projection. The anal excision is shorter. The position of iv, on secondaries is more central, and this appears a more generalized form than either Idaides or Zetides.

I am indebted to the kindness of Dr. Karl Jordan for material of this species. Notwithstanding the differences in shape of hind wings, these three genera are undoubtedly phylogenetically nearly related. The veins are opaque and strong. Pathysa antiphates.

Agrees in one essential neurational feature, the fusion of the first radial branch, with the preceding genera, to which, notwithstanding

' superficial” discrepancies, it may thus be distantly related. The cubital cross-vein is attenuate, and does not reach vein vii. On the secondaries the position of iv, is nearly central. Vein iv, is produced into a long tail, not spatulate. In shape of wing this genus resembles Iphiclides, as also in the slender, transparent

veins, and in the striped character of the ornamentation. It probably occupies an independent intermediate position. The colors in this group, brown and greenish yellow, are peculiar, and, in preparing the wings in the usual manner, they are persistent. Pathysa has striped wings. In Arisbe the bands are indicated by scattered blotches. These latter are gathered into a single series of interspaceal spots in Idaides, on the primaries. These spots coalesce and broaden into a band, which also obtains over the hind wings, in Zetides.

The coincident characters of Pathysa and Iphiclides allow of no other conclusion than that the two are somewhat nearly phylogenetically connected, notwithstanding the fact that in Pathysa the first branch of radius joins subcosta, while in Iphiclides it is free. Assuming that the Second Group contains younger forms, we might have in Iphiclides a type representing a stage through which Pathysa has already passed. But Iphiclides and the members of the Second Group are in one character more generalized than Papilio and its immediate allies, i.e., the straight internal vein of hind wings. We have probably to do with divergencies from a common stock in different directions, in part retaining characters of generalization. It is sufficient here that we show that Iphiclides and Papilio constitute totally distinct genera, having probably a different immediate ancestry. And it remains a possibility that the fusion of the first radial branch with subcosta is a more recent feature, here engrafted upon a wing in other characters representing an older type than Papilio. Thus the Itaides group may be a lateral branch, thrown off before the tendency of the internal vein to curve and shorten on hind wings was developed. And to this branch, as represented by Pathysa, Iphiclides podalirius and allies may be related.

In respect of the curved inner margin of the hind wings, Papilio machaon and allies are more specialized than Iphiclides.

(3d Group.) Pachlioptera aristolochiæ.

The shape and neuration of primaries agree exactly with Eurycus, except that the cubital cross-vein, while narrowing inferiorly, appears to reach vein vii, forcing the submedian fold down to the vein. On secondaries the humeral cell is smaller and vein iv, terminates in a spatulate tail. Veins iv, and iv, are not so near at

base as in Eurycus, than which this form appears more generalized. I do not doubt the validity of the genus.

( 4th Group.) Iphiclides podalirius.

Compared with Papilio machaon the veins are more slender and transparent. Veins iv, and iv, on secondaries are nearer together at base. The internal nervure is straight and the margin fuller on hind wings. On primaries the cubital cross-vein is slighter and does not attain vein vii. The discal cross-vein is downwardly curved on hind wings between iii and ive. The humeral cell is larger than in Papilio.

By the free first radial branch this genus agrees with Papilio and the other genera of the group. Otherwise it is more nearly connected with Pathysa antiphates, and its generic distinction as compared with Papilio is beyond question. The straight internal vein of secondaries is a character of generalization as compared with Papilio. Jasoniades turnus.

Agrees very closely with Papilio. The humeral cell is larger, the tail shorter and a little spatulate. The internal vein is curved, as in Papilio, with which it so closely corresponds as to make the propriety of its generic separation doubtful. The two forms appear to belong to the same immediate phylogenetic line. Euphæades troilus.

The tail is a little shorter and spatulate; otherwise this form agrees so exactly with Jasoniades that I find no distinguishing character whatever. Belongs to the same branch and group. Heraclides thoas.

The tail is a little longer than in Jasoniades and spatulate. Vein iv, on secondaries is a little farther from ivz, so that Heraclides is more generalized. Otherwise I find no differences whatever. From Euphæades I find only the slightly longer tail to distinguish it.

The separation of the preceding forms, except Iphiclides, from each other and from Papilio seems difficult from the neuration. All have the internal vein of secondaries curved and are evidently very nearly related, belonging to the same phyletic branch of the family.

Laertias philenor.

Agrees with Papilio and preceding genera, except that the internal vein of secondaries is straighter and the margin fuller. I think this feature important. The tail is shorter and hardly spatulate. While otherwise resembling Jasoniades, the relative position of iv, is a little more removed from iv, at base. Appears a slightly more generalized type than any of the foregoing, and to represent a stage from which it is probable the preceding (except Iphiclides) have emerged. Menalaides polytes.

Differs from Laertias only in that the tail is shorter and broader, somewhat spatulate. Achillides paris.

Agrees with Laertias and Menalaides, except that the humeral cell narrows a little more outwardly. The tail is a little longer than in Menalaides, from which I cannot otherwise satisfactorily separate it. These three "

genera” appear to be related by the straighter vein vii of secondaries. Orpheides demoleus.

Appears nearest related to Jasoniades. It only differs by the absence of a tail, and in that the præcostal spur is continued, in an even curve, quite to the shoulder of the wing. The internal vein of hind wings is bent as in Jasoniades and allies, with which it should be apparently associated. Nestorides gambrisius.

Not distinguishable structurally from Orpheides demoleus. The præcostal spur is equally continuous, and, although the proportions of the humeral cell are very slightly different, I am of opinion that no sufficient generic characters can be supplied by the neuration. Calaides androgeus.

Agrees well with the preceding, but differs by the median and cubita! branches of the hind wings forming sharp projections, of which that to iv, is, as usual, the longest. On primaries vein iii, yields very slightly to the tendency to be outwardly removed, and arises beyond the exact point of junction of cross-vein.

The following three generic types stand rather apart and by themselves. There is, except the straighter anal vein, nothing in PROC. AMER. PHILOS. soc. XXXVIII. 159. C. PRINTED JULY 7, 1899.

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