294 



Beetles 



when the host larva itself pupates the Stylops pushes one end of its own 

 body out between two abdominal segments of the host, and there gives birth 

 alive to many little triungulins. How the triungulins find their way to 

 their bee-larva hosts is not very clear, but they probably lie in wait in flowers 

 and when a bee conies along they cling to its leg and are thus carried to 

 the nest where the larvae are. There are two genera of Stylopidae in our 

 country, Xenos, which parasitizes the social wasps, Polistes, and Stylops, 

 which parasitizes the mining-bees, Andrena. The triungulins of Xenos, 

 being born in a community nest, can simply roam about over the brood- 

 comb until they they find a wasp-larva to burrow into. 



Rhynchophora. 



In this suborder are included all those beetles known as curculios, wee- 

 vils, bill-bugs, and snout-beetles (excepting the pea- and bean weevils, see 

 p. 281). They are all characterized by the peculiar prolongation of the 

 front of the head into a beak or snout, which may be long, slender and 

 curved, or straight, short, thick, and obtuse. The mouth-parts, of which the 

 small sharp jaws are the conspicuous feature, are situated at the tip of the 

 snout; upper lip (labrum) and palpi are wanting. The antennae arise 

 from the sides of the snout and are angularly bent or "elbowed" in the 

 middle and end in a knobbed or clavate tip. The body is solid and compact, 

 usually strongly rounded above, and many species are thinly or thickly cov- 

 ered with scales. 



Most of the weevils feed, as adults, on fruits, nuts, and various seeds, 

 though some attack stems and leaves, and others hard wood. Many 

 feign death when disturbed, folding up their legs and head and lying 

 inert until danger is past. The larvae are soft, wrinkled, white, footless 

 grubs .which mostly live in fruits, nuts, and seeds. The larvae and adults 

 of the important family Scolytidae, variously called timber-beetles, bark- 

 borers, or engraver-beetles, burrow in the bark and wood of trees living or 

 dead. 



The principal families of the suborder can be separated by the following 

 key.: 



The dorsum of the last segment (pygidium) of the male divided transversely, so that 

 this sex appears to have one more body-segment, when viewed dorsally, than 

 the female. 

 Mandibles with a scar on the anterior aspect. 



(Scarred snout-beetles.) OTIORHYNCHID^. 



Mandibles without scar on the anterior aspect (Curculios.) CURCULIONID^:. 



Pygidium of both sexes undivided. 

 Pygidium vertical; tibiae not serrate. 



(Bill-bugs and gianary-weevils.) CALANDRID^E. 

 Pygidium horizontal; tibiae usually serrate (Bark-beetles.) SCOLYTID.E." 



