II.] METAMORPHOSES OF INSECTS. 33 



animal contracts, and detaches itself from its skin, 

 within which the further transformations take place. 

 In the next stage, which M. Fabre calls the pseudo- 

 chrysalis (Fig. 11), the larva has a solid corneous 

 envelope and an oval shape ; and in its colour, con- 

 sistency, and immobility reminds one of a Dipterous 

 pupa. The time passed in this condition varies much. 

 When it has elapsed, the animal moults again, again 

 changes its form, and assumes that shown in Fig. 12 ; 

 after this it becomes a pupa (Fig. 13) without any 

 remarkable peculiarities. Finally, after these wonderful 

 changes and adventures, in the month of August the 



o *--' 



perfect Sitaris (PL III., Fig. 4) makes its appearance. 



On the other hand, there are cases in which larvae 

 diverge remarkably from the ordinary type of the 

 group to which they belong, without, as it seems in 

 our present imperfect state of information, any suffi- 

 cient reason. 



Thus the ordinary type of Hymenopterous larva, as 

 we have already seen, is a fleshy apod grub ; although 

 those of the leaf-eating and wood-boring groups, 

 Tenthredinidae and Siricidae (Fig. 14), are caterpillars, 

 more or less closely resembling those of Lepidoptera. 

 There is, however, a group of minute Hymenoptera, 

 the larvae of which reside within the eggs or larvae 

 of other insects. It is difficult to understand why 

 these larvae should differ from those of Ichneumons, 

 which are also parasitic Hymenoptera, and should be, 

 as will be seen by the accompanying figures, of such 

 remarkable and grotesque forms. The first known of 

 these curious larvae was observed by De Filippi, 1 who, 



1 Ann. and Mag. of Nat. Hist. 1852. 

 5 D 



