336 NATURAL HISTORY OF ARTHROPODS. 



finely spotted with cream-white and with black. This beetle is found in species of 

 fungus which grow upon trunks of dead trees. 



Larvffi of species of Brachytarsus, another anthribid genus, are parasitic in the 

 females of different kinds of Coccidas, where they eat the eggs of the scale-insects. 

 This is an exceptional mode of life for weevil larvas ; the majority of them feed upon 

 vegetable matter. 



The Brenthid^ are very elongated wee\ils, probably the most elongated, propor- 

 tionately, of all beetles Brenthus anchorago, of tropical America as far north as 

 Florida, is about 1.40 inches long and only 0.12 of an inch wide at its broadest part. 

 Still more peculiar than their extreme attenuation is the secondary sexual characters 

 of their raouth-parts to accord with their functions. In Exi.psalis, which differs from 

 Brenthus in having a convex thorax without grooves, the female has a prolonged 

 proboscis, with the mandibles at its tip, as is common among weevils ; with this 

 proboscis she bores holes into the bark of the trees which are to furnish food for 

 the larvae, and in each hole she deposits an egg. The male, liaving no such work to 

 perform, has no proboscis, but is pro^■ided with strong, curved mandibles of the 

 ordinary type found in beetles. The males have combats for the possession of the 

 females ; and, although they cannot injure one another on account of their hard ohiti- 

 nous shells, sooner or later one of the combatants withdraws, tired of the battle, leaving 

 the other in possession of the female. While the female is occupied in boring a hole 

 for an egg, an ojDcration which takes about a da_y, the male guards her and strives to 

 drive away any other males that approach. Mr. A. R. Wallace says of the Brenthida3, 

 that it is interesting, " as bearing on the question of sexual selection, that in this case, 

 as in the stag-beetles, where the males fight together, they should be not only better 

 armed, but also much larger than the females." 



Eupsalis minutais distributed throughout the eastern United States 

 and Canada, although most of the Brenthidse are confined to the tropics. 

 It is shining mahogany-brown, with fine yellow spots on the elytra, and 

 is very variable in size, males sometimes measuring over 0.75 of an inch 

 long, while females are now and then found that are not over 0.25 of 

 an inch long. The elongated larva of JS. minuta^ which has been 

 Fig. 376. — Eup- described by Dr. C. V. Kiley, inhabits decaying oak wood, around 

 miis minuta. ^j^j^j^ ^j^^ \,Qei\es are not rare. 



The ScoLYTiD^ are small beetles, some of them almost microscopic, all having a 

 similar general aspect and a nearly cylindrical form, and are, for the most part, of a 

 brown color. The head is usually short, and imbedded in the anterior end of the 

 prothorax ; the proboscis is short, often not apparent ; the antennae are small, genicu- 

 late, clubbed ; the tibiae ai-e usually serrate ; the horizontal pygidium is undivided in 

 both sexes, and is surrounded at its edge by the elytra. Both the mature beetles and 

 their larvae bore in plants, usually trees, on which they feed, often between the bark 

 and wood, — more accurately speaking in the liber, — and their channels, revealed by 

 pulling off the bark, exhibit many curious forms characteristic of the species or genera 

 of Soolytidae to which they pertain. These beetles are especially destructive to Coni- 

 ferse; some species attack other trees, and a few injure herbaceous plants. 



The peculiar forms taken by the mines of tTiese beetles in wood and bark are 

 dependent upon the mode of oviposition of the different species. The males form 

 chambers (" Rammelkammer " of K. Lindemann) in the bark, in which they await the 

 females. After pairing, the females enlarge and prolong this copulation-chamber, 



