COLEOPTERA 513 



worms in appearance. There are more than one hundred described 

 North American species. 



Family TENEBRIONID^ 



The Darkling Beetles 



The darkHng beetles are nearly all of a uniform black color, 

 although some are gray, and a few are marked with bright colors. 

 The different species vary greatly in size and in the form of the body. 

 The hind tarsi are four-jointed, and the fore and middle tarsi are 

 five-jointed. For other characters, see table, p. 474. 



These insects occur chiefly in dry and warm regions. Thus while 

 we have comparatively few species in the northeastern United States, 

 there are many in the Southwest. Most of the species feed on dry 

 vegetable matter, and often on that which is partially decomposed; 

 some live in dung, some in dead animal matter, others in fungi, and 

 a few prey upon larvae. More than eleven hundred species occur in 

 this countr3\ The three following will serve to illustrate the variations 

 in form and habits. 



The meal-worm, Tenebrto molitor. — This is a well-known pest in 

 granaries and mills. The larva is a hard, waxy yellow, cylindrical 

 worm, which measures when full-grown 25 mm. or 

 more in length, and closely resembles a wire-worm; 

 it feeds on floiu* and meal. The beetle is black and 

 about 15 mm. in length, (Fig. 615). The larvae 

 and pnpsc are used for bird-food and are grown in 

 quantity by bird-supply houses. 



ThefoTkedinngus-heetle,Boletotheruscornutus, 

 is common in the northeastern United States and ^^S- Fig- 



in Canada about the large toadstools {Poly poms) '^' ' ' 



which grow on the sides of trees. The surface of the body and wing- 

 covers is very rough, and the prothorax bears two prominent horns 

 (Fig. 616). The larva lives within the fungi referred 

 to above. 



The pinacate-bugs. — Several species of Eleodes 

 are abundant on the Pacific Coast, where they are 

 found under stones and pieces of wood h'ing on the 

 ground. They are apt to congregate in large numbers 

 under a single shelter, and are ckunsy in their move- 

 ments. They defend themselves when disturbed by 

 elevating the hinder part of the body and discharging 

 an oily fluid from it. They present an absurb appear- 

 ance, walking off clumsily, and carr^'ing the hind end 

 of the body as high as possible. The most common 

 Fig. 617. species are large, smooth, club-shaped beetles (Fig, 



617), and are commonly known as pinacate-bugs. 

 These beetles and those belonging to several closely allied genera lack 

 hind wings. 



yellow, cyiinaricai 



