n8 INSECT TRANSFORMATION 



the air to the nest of the host-bee, and the latter being assumed 

 when it finds itself in shelter amid a rich and abundant supply 

 of food. 



A somewhat similar hypermetamorphosis is found also 

 among the Strepsiptera 1 very small insects whose males 

 (Fig. 67 a) have the reduced forewings narrow and twisted, 

 and the broad hindwings developed for flight, while the 

 degraded wingless and legless females (Fig. 67 b) remain within 

 the bodies of insects (mostly wasps, bees and froghoppers) 

 in which the larvae live as parasites. The tiny first-stage 

 larvae are active and armoured with long feelers and legs, but 

 the feet bear suckers instead of claws (Fig. 67 c). Hatched 

 within the mother's body, they emerge and crowd over the 

 host's cuticle. Those of them which find opportunity, bore 

 into a host-insect in the larval stage ; then they moult and 

 assume the legless, soft-cuticled form suitable to their parasitic 

 manner of life (Fig. 67 d). In the subsequent life-history of 

 the male, the most remarkable features are the development of 

 a pre-pupal instar with wing-rudiments inside the separated 

 larval cuticle, and the subsequent development of a pupa inside 

 this, so that the emerging male has three cuticles to break 

 through. The female never comes out of the hardened larval 

 cuticle. 



While the beetles exhibit great variety in the structure of 

 their larvae, in most groups of insects we find some form that 

 is especially characteristic of each order. If, for example, we 

 take that assemblage of families in which the perfect insect 

 has biting jaws much like those of beetles, but has all four 

 wings membranous and net-veined (the order Neuroptera of 

 most modern entomologists), we find larvae of the campodeiform 

 type, resembling often in their general build the grubs of ground- 

 beetles except that the characteristic cerci or tail-feelers are 

 wanting. The larva of the alder- fly (Sialis), a common inhabi- 

 tant of the muddy bottom of ponds and sluggish streams, has 

 a broad head and thorax, and a long tapering abdomen, all 

 the segments being strongly chitinized. The head carries fairly 

 prominent, four-segmented feelers, formidable mandibles 



1 W. Kirby : " Strepsiptera, a new Order of Insects ". Trans. Linn. 

 Soc., XI. 1813. W. D. Pierce: " A Monographic Revision of the Twisted- 

 winged Insects ". Bull, 66. U.S. Nat. Mus. 1909. 



