HYMENOPTERA. — ICHNEUMONIDE. 147 
The larvee of these insects (fig. 76. 12.) are destitute of feet, having a 
soft, white, fleshy, and nearly cylindrical body, with lateral fleshy tu- 
bercles, generally slightly curved and narrowed at each extremity ; the 
first segment, or the head ( jig. 76. 14.), furnished with two distinct 
round points in those larvee which I have examined, resembling ocelli, 
beneath which is a transverse fleshy upper lip, and two obliquely 
deflexed horny mandibles, very small, slender, and acute: beneath 
these is a curved fleshy lcbe of three parts, formed by the union of 
the dilated maxillz and labium. Réaumur has rudely represented these 
parts (Mém. tom. ii. pl. 33. f. 4.) ; but he describes the head as being 
concealed by a sort of ‘‘ chaperon charnu ” (fig. 3. cc.) which I have not 
recognised in my various larve of this family. The figure given by Ly- 
onnet of the head ( fig. 76. 15.) of the larva of Ophion luteum agrees 
with my observations ( Posth. Mém. pl. 24. fig.’7.)* Those larvae which 
reside, like the intestinal worms, within the bodies of caterpillars 
(sometimes in society), as the Microgasters, which infest the cater- 
pillars of the white butterflies ( fig. 76. 16.), carefully avoid touching 
the vital organs of their victims, feeding only upon the fatty matter : 
when, however, they have attained their full size, and are ready to 
assume the pupa state +, they pierce the skin of the larva, which soon 
dies, spin for themselves cocoons beneath its body (or within the 
cocoon which it had formed for its own grave), and undergo their trans- 
formations. Such are the habits of the minute species of Micro- 
gaster which attack the common cabbage-butterfly, and which deposit 
a great number of eggs in the same caterpillar, so that the parasitic 
larvee, when hatched, live in society (Réaumur, Wém. tom. ii. pl. 34.) ¢ ; 
whereas many species deposit only .one, or but very few eggs, in the 
body of a caterpillar. The larve of other species do not destroy 
their victim in its larva state, but allow it to become a pupa, in the 
body of which they undergo their transformations, not making their 
* De Geer’s figures of the head of the larva exhibit the acute mandibles, but the 
fleshy lips are of different forms to those described above. (Mém. yol. i. pl. 34. 
f2 11. and! 12: 
+ M. Audouin has described a small species (Ophion Dosithee), the larva of 
which continues to feed upon the caterpillar of the Dosithea after it has burst forth ; 
and which partially employs the skin of the caterpillar in constructing its own 
cocoon. (Ann. Soc. de France, 1834, p. 417.) 
¢ The Rev. W. Bree and Mr. Newman have publishedssome obseryations on 
this genus (Mag. Nat. Hist. No. 23., and Westwood in Ditto, No. 25.); Mr. 
Newman noticing a filiform appendage attached to the tail of the larva of the Mi- 
crogaster, which he suggests may serve as an umbilical cord for taking food. 
iD A 
