388 THE ANATOMY OF INVERTEBRATED ANIMALS. 



gle pair of wings, which are attached to the metathorax, 

 while the mesothorax has a pair of twisted appendages in the 

 place of wings. 



The larvae of both males and females when they leave the 

 egg are minute active hexapod insects (Fig. Ill), with rudi- 

 mentary manducatory organs, and are found creeping about 

 between and on the hairs with which the abdomen of their 

 host is provided. In this condition they are carried into the 

 nests of the bees, and they attack the larva? of the latter, bor- 

 ing their way through the integument into the abdominal 

 cavity of the grub. Here they cast their cuticle and become 

 changed into sluggish apodal grubs, provided with a mouth, 

 with rudimentary jaws, and with an alimentary sac, but de- 

 void of an anus. About the time that the Hymenopterous 

 larva passes into its imago state, the Strepsipteral larva 

 thrusts the anterior end of its body (the so-called cephalo- 

 thorax) between two of the abdominal segments of the bee, 

 so that it projects externally. The male becomes a pupa, and 

 eventually makes its way out as a winged insect. The fe- 

 male, on the other hand, undergoes little change of outward 

 form, but presents an opening, which plays the part of a 

 vulva, and enables the male to effect the fecundation of the 

 eggs. These are developed within the body of the female, 

 and make their way out by the cleft in question. 1 



The Ichneumon-flies deposit their eggs within the bodies 

 of the larvae of other insects, and the grubs thence hatched 

 devour the corpus adiposum of their host. The larvae of 

 some of these parasites (Platygaster, Teleas), described by 

 Ganin, 2 are extraordinarily unlike other insect larvae, and 

 have a certain resemblance to Copepoda. 



1 See Von Siebold " Ueber Strepsipteren " (" Arcliiv fur Naturgeschiehte," 

 1843), and Newport, "Natural History, etc., of the Oil-beetle, Melde" ("Linn. 

 Trans," 1847). 



2 Zeitschrift fur Zoologie, 1869. 



