220 SYSTEMATIC ZOOLOGY 



film of air which adheres to the minute hairs on the ventral sur- 

 face of the body; they come to the surface from time to time 

 to renew this air. The brilliant green Spanish flies belong to 

 the beetles ; also the little ladybirds, or ladybugs, of which there 

 are over a thousand species, the weevils or boring beetles, and 

 the glow-worms or fire flies. Here, too, are the scarabs, dull 

 black beetles, sometimes from two and a half to three centi- 

 meters long, of which the sacred Egyptian scarab, Scarabceus 

 sacer (Fig. 223), is familiar from Egyptian carvings. 



The buffalo bug or carpet beetle, Anthrenus scrophularice 

 ( Fig. 224), is a very troublesome beetle apparently imported to 

 the United States from Europe ; it is only about three milli- 

 meters long, and feeds out of doors on the pollen of flowers, 

 indoors on carpets and all kinds of woolen goods as well as 

 on furs and similar objects ; the larva, which is covered with 

 long brown hairs, is, as usual with insects, more destructive than 

 the adult. The adult buffalo bug is black marked with white and 

 brick-red spots, and has the elytra covered with minute scales. 



Many of the weevils are destructive to various plants, trees, 

 and fruits ; such are the potato-stalk weevil, the white-pine 

 weevil, the pea weevil, and the plum weevil, which stings the 

 plum and deposits an egg within the fruit; the cherry, peach, 

 and quince are attacked in a similar way. Many larvae are very 

 destructive borers in wood, particularly the larvae of the long- 

 horned beetles, which have very long antenna" ; these larvae 

 sometimes live for two or three years before passing into the 

 pupal stage ; when about to do so they often make a sort of 

 cocoon for themselves out of fine chips of wood, which they 

 fasten together. 



Some beetles feed on the leaves of plants or on the petals of 

 flowers. The rose bug or rose chafer is a familiar example. 

 One of the most troublesome in this country has been the Colo- 

 rado or potato beetle, Doryphora decemlineata (Fig. 225). Both 

 the adult beetle and the larva feed on the potato leaves. The 

 bright yellow eggs are deposited in groups on the under sur- 

 face of the potato leaves ; the larva? grow rapidly and then 

 descend into the ground, where they pass into the pupal stage, 

 and shortly after emerge as fully developed beetles within a 

 month after the time of hatching from the egg. Some beetle 



