Beetles 293 



get on to the body of the female of one species of bee; but it has no dis- 

 crimination whatever of the kind of object it requires, a'nd, as a matter of 

 fact, passes with surprising rapidity on to any hairy object that touches it; 

 hence an enormous majority of the young are wasted by getting on to all 

 sorts of other insects; these larvae have been found in numbers on hairy 

 Coleoptera, as well as on flies and bees of wrong kinds; the writer has ascer- 

 tained by experiment that a camel's-hair brush is as eagerly seized, and 

 passed on to, by the young Meloe as a living insect is." 



The commonest Eastern species of blister-beetles belong to the genus 

 Epicauta. They feed when adult on the leaves of potato being therefore 

 often called potato-beetles and on the pollen of goldenrod. E. pennsyl- 

 vanica is uniformly black; E. cinerea is grayish black or even ashy, always 

 with the margins of the elytra gray; E. vittata (Fig. 401) is yellowish or reddish 

 above, with head and prothorax marked with black and with two black stripes 

 on each elytron. In Meloe the wings are lacking and the elytra short and 

 diverging; M. angusticollis, the buttercup oil-beetle, ^ to f inch long, 

 of violaceous color, is the commonest eastern species. In the west the 

 commonest blister-beetles are metallic green and blue and belong to the 

 genus Cantharis. 



Another small family of rarely seen heteromerous beetles, which, how- 

 ever, possess an extremely interesting and wonderfully specialized life-history 

 and show a marked degenerate structure due to their parasitic habits, is 

 the Stylopidae, or wasp parasites. Indeed these 

 curiously modified beetles differ so much from 

 all the other Coleoptera that some entomolo- 

 gists look on them as composing a distinct order 

 which these naturalists call Strepsiptera. The 

 males are minute with large fan-shaped wings 

 and reduced, short, club-like elytra. The 

 females are wingless and never develop beyond 



a larval or grub-like condition. They live in FIG. 4 o 3 .-A wasp, 



' parasitized by (x) Xenos sp. 



the body of a wasp or bee (Fig. 403) certain (After Jordan and Kellogg; 

 foreign species parasitize ants, cockroaches, and slightly enlarged.) 

 other insects while the free-flying males live from only fifteen or twenty minutes 

 to a day or two: three days is the longest observed lifetime of active adult 

 existence! The youngest larva of the Stylopids the" egg-laying has not 

 been observed is a minute, active, six-legged creature, not unlike the Meloid 

 triungulin, which attaches itself to the larva of a bee or wasp and burrows 

 into its body. There it lives parasitically, meanwhile undergoing hypermeta- 

 morphosis in that after its first moult it becomes a footless maggot or grub. 

 In this state it continues until, if a male, it pupates in the host's body and 

 issues for its brief active adult life. If a female, there is no pupation, but 



