URBICOLÆ—HESPERIDES.
THANATITES Scudder.
Very much of the general appearance of Thanaos Boisd. ([Pl. III], fig. 11) but with somewhat differently formed wings and markings which will not accord with those of the latter genus, although the two genera are certainly nearly allied.
The body ([Pl. III], fig. 12) is fully as stout as in Thanaos ([Pl. III], fig. 11), the tongue at least as long as the thorax, the eyes ovate and larger, than in Thanaos, and the palpi with the terminal joint proportionally larger, which is an unusual feature in the Urbicolæ. The legs are apparently short, the wings ample. The costal margin of the fore wings is nearly straight, being scarcely arched on the apical half, the upper half of outer border as in Thanaos, the rest not preserved; the costal fold of the male is narrow and extends a very little beyond the middle of the costal border, while in Thanaos it reaches considerably further; the hind wings have the general shape of Thanaos, but the upper outer angle is much more produced, and the base of the costal border is arched only to the degree that the apex is, and the portion between them is but slightly convex; the outer border is almost precisely as in Thanaos and the inner border is, doubtless, folded in the fossil so as to conceal its true character. Very little of the neuration can be determined, and what can be made out is comparatively unimportant and agrees with the neuration of Thanaos; the third superior subcostal nervule strikes the apex of the fore wing as in that genus. As to the markings, the agreement with Thanaos is less striking, although the pattern resembles that of Thanaos more closely than it does that of any other genus. In the fore wings the spot in the cell of Thanaos is wanting in the fossil, but in its stead there is a costal spot at the extremity of the costal fold; the subapical spots of Thanaos depending from the costa are distinctly repeated in Thanatites, and in addition there is a submarginal series of small round spots of which the upper two, in the uppermost interspaces opening on the outer border, are the only ones visible on the fossil by its mode of preservation. On the under surface of the hind wings of Thanatites, there is a regular submarginal series of equal, rather small, round spots, one in each interspace, placed between the location of the marginal and submarginal spots which occur in Thanaos, often distinctly, occasionally as faint blurred bands, as in T. Juvenalis ([Pl. III], fig. 11); the inner of these two series in Thanaos, which corresponds best to the submarginal series of Thanatites, is irregular instead of parallel to the border, being always bent inward opposite the cell. Instead of the spot, placed in the costo-subcostal interspace of Thanaos near the middle of the wing, and seen distinctly in T. Juvenalis, there are two spots, which, with a third near the base of the wing above the costal nervure, are placed at equal distances apart and from the costal border; in addition there are two spots, seldom even indicated in Thanaos, near the centre of the wing, the larger of which is near the apex of the cell. These differences alone would suffice to show that the fossil cannot be referred to Thanaos, and, with the other indications we have given, compel us to place it apart, but in the immediate vicinity of this group of Urbicolæ.
THANATITES VETULA (Heyden) Scudder.
[Plate III], figs. 12, 16.
Vanessa vetula Heyd., Palæontographica, viii, 12-13, Taf. i, fig. 10 (1859).
Araschnia vetula Kirb., Syn. Cat. Diurn. Lep. 179 (1871).
The only notice of this insect that has been published is the original figure and description of von Heyden. The figure is reproduced in our [Pl. III], fig. 16. The description is as follows:[AF]—
Es scheint diese Art in die Nähe der bei uns lebenden Vanessa Levana zu gehören. Sie ist kleiner als diese, indem der Vorderflügel von seiner Basis bis zur Spitze nur 6½‴ misst. Der Schmetterling liegt auf der rechten Seite, wobei der linke Hinterflügel den linken Vorderflügel völlig bis auf die Spitze und einen Theil des Aussenrandes deckt. Von diesen Flügeln ist daher nur die Unterseite sichtbar. Der rechte Vorderflügel ist mehr vorgeschoben und daher ein grosser Theil seiner Überseite sichtbar.
Die Flügel sind im Allgemeinen gut erhalten und scheinen am Aussenrande an einigen [13] Stellen schwach ausgerandet gewesen zu seyn. Sie zeigen auf der Grundfarbe grössere, undeutlich schwarze und viele weisse Flecken von verschiedener Grösse. Auf den Vorderflügeln zeichnen sich ein grösserer weisser Flecken, etwa ein Drittel von der Spitze entfernt und nach dem Vorderrande hinzielend, sowie drei weisse Fleckchen aus, die in einer Reihe in der Nähe des Aussenrandes stehen. Auf den Hinterflügeln, etwa ein Drittel vom Aussenrand entfernt, bilden sechs weisse Fleckchen eine Querreihe. Es ist nicht unwahrscheinlich, dass die Grundfarbe der Flügel im Leben braun oder rothbraun war, und man glaubt sogar noch einen schwachen Schimmer von dieser Farbe wahrzunehmen.
Der Kopf ist etwas zerdrückt und zeigt zwei ziemlich lange, zugespitzte, in die Höhe gerichtete Taster, von denen der eine vom Kopf getrennt liegt. Oben am Kopf ist noch ein Auge und unten die in einen Bogen aufgerollte Zunge sichtbar. Die Brust ist undeutlich, der Hinterleib fast ganz durch die Flügel gedeckt, und von den Beinen sind nur Bruchstücke vorhanden.
Dark brown or blackish with light markings. On the upper half of the fore wing ([Pl. III], fig. 12), both above and below, the following markings are found: a small quadrate spot on the costal border at the extremity of the costal fold; depending from the costal border between the tips of the second and third superior subcostal nervures a confluent series of spots extending to the cell at right angles to the costal margin, narrowing a little in passing downward; and midway between this and the outer border, in the upper two subcostal interspaces opening on the outer border, a small round spot; probably similar spots belong in some of the interspaces below. On the under surface of the hind wings there is a submarginal series of three small spots along the costa at equal distances apart, the central one near the middle of the costa, and the basal one nearly midway between it and the base of the wing; there is also a larger spot near the tip of the cell and a second smaller one a little below and beyond it; also a submarginal series of spots as large as that in the cell parallel to the outer border, at about an interspace’s distance from it, one in each interspace. Length of fore wing, 14mm.; length of hind wing, 13·65mm.; extreme breadth of hind wing, 11·25mm..
The single fossil represented by von Heyden under the name of Vanessa vetula, is preserved on a greasy, dark brown, thin and exceedingly fragile sheet of “brown coal,” and is likely to become so affected by weathering as to be almost or quite indistinguishable in the course of time. Indeed it is excessively obscure at the present time, and no fossil object I have ever studied has proved so difficult to decipher as this. It represents an insect ([Pl. III], fig. 12) lying upon its side in a somewhat natural attitude (compare fig. 11), so that one can see the whole of the under surface of the left hind wing, the costal quarter of the under surface of the left fore wing, and a little more than a quarter of the upper surface of the right fore wing, also of the costal area; the thorax and head with the eyes, the denuded palpi, the partially unrolled tongue and fragments of the legs in a confused medley may also be seen, but there is no trace of the antennæ, nor of the right hind wing (nor of the abdomen?). The left hind wing has an immaterial part of its outer border removed, and a small portion of the outer border of the left fore wing is also wanting, but the corresponding portion of the right fore wing is present. The markings can only be made out by extreme care, and a very meagre portion of the neuration, especially toward the borders of the wings, by great patience and the closest examination; but most of what can be seen of the neuration adds but very little to our actual knowledge of the animal; it simply adds its testimony in the same direction as other features of the object.
The illustration of von Heyden ([Pl. III], fig. 16) is faulty in several particulars, but this is not surprising when we consider the excessively obscure nature of the fossil; it represents the insect as if the under surface of both wings of one side were seen, the fore wing concealing a portion of the hind; a break in the stone is taken for the outline of the wing (just above the extremity of the costal border of the hind wing) and the markings of the two front wings are blended into one; an abdomen is represented and above it an outline of the inner border of the hind wing. The fossil has at first sight this appearance, but I think this view is erroneous, although on this point one may not speak with confidence, and it is comparatively unimportant. It is remarkable, however, that von Heyden, in his description, takes the same view of it as I have done. I have not attempted to give the shading of the darker parts of the wing, partly from its obscure nature, partly from a doubt whether they really represent the original markings of the insect; for the basal half of the under surface of the hind wings, where most of the dark mottling in Von Heyden’s figure occurs, is usually devoid of any such variegation in the insects of this group; they are almost always of a uniform grayish or brownish hue. Von Heyden’s figure does not show the division of the palpal joints.
Tertiaries of Rott, Rhenish Provinces of Germany. British Museum.