DEVELOPMENT 145 



shortly emerges. Thus the pupal stage is preceded by at least three 

 distinct larval stages. 



In the anomalous beetle Stylops, the males are winged, but the fe- 

 males are maggot-like and sedentary, living in the bodies of bees and 

 wasps. Packard found as many as three hundred triungulin- larvae 

 issuing from a female Stylops in the body of an Andrena. The further 

 life history of Stylops is but imperfectly known ; probably the triungulin 

 climbs upon a bee or a wasp and enters its body, after the manner of the 

 European Rhipiphorus paradoxus, whose life history is much better 

 understood. 



FIG. 218. Stages in the hypermetamorphosis of Epicauta. A, triungulin; B, carabidoid 

 stage of second larva; C, ultimate stage of second larva; D, coarctate larva; E, pupa; F, 

 imago. E is species cinerea; the others are vittata. All enlarged except F. After RILEY, 

 from Trans. St. Louis Acad. Science. 



The most extraordinary metamorphoses have been found among 

 parasitic Hymenoptera, as in Platygaster, a proctotrypid which infests 

 the larva of Cecidomyia. The egg of Platygaster, according to Ganin, 

 hatches into a larva of bizarre form (Fig. 219, A), suggesting the crusta- 

 cean Cyclops, rather than an insect. This first larva has a blind food 

 canal and no nervous, circulatory or respiratory systems. After a moult 

 the outline is oval (B), and there are no appendages as yet, though the 

 nervous system is partially developed. Another moult, and the third 

 larva appears (C), elliptical in contour, externally segmented, with 

 tracheae and a pair of mandibles. From now on, the development is 

 essentially like that of other parasitic Hymenoptera. 



