STREPSIPTERA. 297 
Within this last-named pellicle I also observed near its posterior 
extremity another crumpled-up mass of pellicle of a dark opake 
colour, perfectly distinct from the pellicle of the larva itself, and which 
had evidently formed the covering of the enclosed pupa, and had been 
shed by it previous to the time when the imago had escaped. Hence, 
as well as from the account given by Jurine, it is evident that the 
pupa of the Stylops is enclosed in a distinct skin, and is also in that 
state enveloped by the skin of the larva *, contrary to the suggestion 
of Mr. Kirby (Zinn. Trans. vol. xi. p. 97.); and hence the accounts 
and figures given by most authors of the pupa of these insects are in 
fact merely representations of the larva in an altered form, but totally 
different from that of the real pupa, which no author, except Jurine, 
has seen.t Figure 93. 16. is copied from Curtis’s Brit. Ent. pl. 226, 
and is described by that author as a pupa in which the head is wider, 
the eyes appearing through, and in a different situation, and the 
inferior wings are folded laterally; in a specimen of the imago, ex- 
tracted from the pupa, they met over the body. (Curtis's Addend. to 
Stylops.) 
Jurine’s figure of the larva of Xenos Vesparum Fosst (Turin 
Trans. vol. xxiii. f. 3.) differs from that given above of Stylops; the 
head being represented as small, and succeeded by a very large nearly 
quadrate segment, with two frontal and several longitudinal tubercles, 
followed by eight transverse joints, gradually narrowed to the end of 
the body. Professor Peck’s figures of the larva cf X. Peckii represent 
the body as consisting of a regular series of transverse segments. These 
figures disagree, however, with specimens of the larve of X. vesparum, 
kindly sent to me, in spirits, by the Senator Van Heyden, of Frank- 
fort on the Maine, together with specimens of the pupa in different 
stages of development, the larve precisely agreeing with those of 
* « He pupe, siacis ope e loco penitus extrahantur abruptoque tegumento leniter 
deinde tunica seu veste alba propria exuantur.” ( Rossi.) Professor Peck, indeed, 
figures the head of the pupa as furnished on each side, behind, with a number of 
pellucid hexagons (Linn. Trans. vol. xi. pl. 8. fig. 7.), whence Mr. Kirby was 
led to suppose that the skin of the head, at least of the larva, had been rejected 
(but I have never seen any thing analogous to this in the exserted heads of the pupzx 
of Stylops); and hence Mr. Kirby considers the metamorphoses of these insects as 
intermediate between incomplete and coarctate. 
+ Dufour describes the larva of Xenos Rossii in its first states but his description 
of the pupa is merely that of the larva in its altered form. (Ann. Sci. Nat. Jan. 
USS pleads An tise 15.) 
