STREPSIPTERA, 9295 
various bees and wasps*, the larva, when full-grown, protruding its head 
between the abdominal segments of these insects, appearing, at first 
sight, like a small flattened acarus. The full-grown larvee of Stylops 
are nearly cylindrical fleshy grubs, about a quarter of an inch Jong 
(fig. 93.10. laterally, 93.11. dorsally viewed), of a white colour, with 
the head distinct and flattened, and attached to the body by a narrow 
neck: the head is not at this time provided with distinct mandibles, 
&c., but appears only to be provided with several small elevated 
tubercles (fig. 93.12. front of upper side of the head, 93.13. ditto 
under side), behind which is a transverse impression; and the posterior 
angles of the head are rounded and elevated. In several larva which 
I have examined in a living state, the anterior part of the dorsum 
exhibited a more distinctly coriaceous texture, and seven articulations ; 
but the terminal part was quite exarticulate. Mr. Kirby describes 
the supposed pupa of S. Melitta in a similar manner. (Linn. Trans. 
vol. il. p. 233.) The precise manner in which this larva feeds is not 
known: Professor Peck, however, distinctly states, that in the feed- 
ing state the head of the larva is near the base of the abdomen of the 
wasp, as he found by dissection; and that, when the feeding state is 
passed, it is easy to conceive that it turns, and with its flattened head 
separates the membrane which connects the abdominal scuta, and pro- 
trudes itself a little way, accurately closing the aperture, which is but 
* The presence of these parasites is at once indicated by the swollen and distorted 
appearance of the abdomen of the bee or wasp. ‘There are generally two or three 
parasites in each infested insect, but in a Polistes gallica, presented to me by Mr. 
Broome, there are no less than five of the heads of the larva of Xenos exserted 
(fig. 93. 20.); and Jurine mentions having observed as many as six entirely within 
the body of a Polistes. Upon comparing the volume of the internal air vessels and 
abdominal viscera of a stylopized bee with those of one not thus attacked, I imme- 
diately observed that the former were very considerably reduced in size; and 
although the ovaries were easily perceived in the unattacked individual, I was unable 
to perceive them in the former: hence I should consider that Mr. Kirby’s 
supposition that the presence of these parasites renders the insects attacked abortive, 
is well founded. They do not destroy the bee or wasp, as it is not an uncom- 
mon circumstance to meet with these insects with the exuvie of the Strepsiptera 
still remaining inthem. M. Dufour states that they “n’attaquent point les viscéres 
de linsecte, et ne vivent qu’aux dépens de son tissu adipeux splanchnique. (Anz. 
Sci. Nat. Jan. 1837. p.19.) Mr. Kirby states, that he does not recollect observing 
the exuvie in a male bee. (Jntrod. to Ent. vol. iv. p. 209.) They are certainly 
found for the most part in female bees, but I have known them occur in individuals 
of the opposite sex. (And see Ent. Mag. vol. ii. p. 327.) Jurine also observes, 
that male Polistes are attacked as well as females. 
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