THE HIDDEN TYPE OF WING-GROWTH 121 



of larval life, the Psychopsis has a much broader head, with 

 long feelers of nine or ten segments (Fig. 68 d) ; through all 

 the larval stages the jaws remain of essentially the same 

 form, the labium having a narrowly triangular base which 

 carries long, five-segmented palps. The general form of the 

 larval body during the third stage, which lasts nine months, is 

 much the same as during the second. The expanse of flexible 

 cuticle on each segment is strengthened by a pair of small, 

 hard, brown, bristle-bearing plates. In many larvae of the 

 group the " ant-lions," and " aphid-lions " or grubs of the 

 lacewing flies for example such plates may be numerous and 

 prominent, so that the larval body becomes quite strongly 

 armoured. 



There is a family of remarkable insects, the Mantispidae, 

 allied to those just described, whose members, found in 

 southern Europe and in the tropics, are distinguished by the 

 possession of an elongate prothorax which carries a pair of very 

 strong spinous front legs adapted for catching prey. From the 

 long-stalked eggs of a Mantispa 1 are hatched typical little 

 campodeiform larvae like the oil-beetle's triungulin (p. 116 

 above) these live from autumn till spring without feeding ; 

 then they penetrate into the globular egg-cocoon carried about 

 by a female hunting spider (Lycosa), and attack the young 

 spiders as they are hatched, piercing them with pointed 

 mandibles and sucking out their juices. Such feeding leads to 

 an expansion of the larva so that the cuticle covering its swollen 

 body-segments becomes stretched, and it assumes the appear- 

 ance of a chafer grub. Later on it undergoes a moult, and then 

 it is transformed into a soft-bodied grub, very stout in its 

 middle region, tapering to the tail-end, its head relatively very 

 small, and the legs on its thoracic segments greatly reduced. 

 In this condition it rests, amidst the dried remains of its young 

 spider victims, until the time for its pupation shall have 

 arrived. The life-history of Mantispa affords, therefore, like 

 the transformation of the oil-beetles, an example of hypermeta- 

 morphosis. 



Another order of insects whose larvae illustrate an interest- 

 ing transitional type, are the caddis-flies (Trichoptera). These 



1 F. Brauer : " Beschreibung der Verwandlungsgesckichte der Mantispa 

 styriaca ". Verhandl., K. K. zool. hot. Gesellsch. Wien., XIX. 1869. 



