332 



NATURAL HISTORY OF ARTHROPODS. 



years for its metamorphoses. The beetles frequent the leaves of oaks, appearing 

 during June in France. 



To the genus Callidium, in its less restricted sense, belong flattened species of 

 longicorns with i)rothorax and elytra spineless, with eyes not embracing the base of 

 the antennas, and having the femora usually much thickened. Some of the species of 

 this genus are very variable ; C. variabile, a species common both in Europe and 

 America, has over twenty well-defined varieties. It is often entirely brownish yellow, 

 sometimes the prothorax only is brownish or reddish yellow, while the rest of the 

 beetle is deep blue. Its larva feeds in oak. C. antennatum, of the United States, 

 and O. violaceum, of Europe, are both entirely of a very deep metallic-blue color. 



Both feed, as larvae, upon 

 conifers. 



Hylotrupes bajulus is 

 similar in form to Callid- 

 itim, but has a broader pro- 

 sternum. Its prothorax is 

 nearly round. Tlie entire 

 beetle is usually black, 

 clothed in places, especially 

 on the prothorax and elytra, 

 with ashy pubescence, but 

 sometimes the el^ytra are 

 brownish yellow. Its length 

 is about 0.75 of an inch. 

 The larvae eat the wood of 

 conifers, and, according to 

 Kirby and Spence, have done much damage to rafters and roofs in London ; when the 

 beetles arrive at maturity they even pierce sheets of lead to escape from the wood. 

 This species is found near the coast in North and South America, where it has been 

 introduced from Europe. Asemiim mcestum, an American species, is similar in form 

 to If. bajulus, but is somewhat smaller 

 and of a dull, dark brown color. Its larva 

 bores in pine wood. 



The last sub-family of the longicorns, 

 the Prioninae, which haxe a margined 

 prothorax, are mostly insects of consider- 

 able size, with strong jaws. In some 

 .species, of which Macrotoma lethifer is 

 an example, the males are eight or U'li 

 times more numerous than the females, 

 and fight among themselves for the pos- 

 session of the females. In these fights 

 the males bite off one another's antenna 

 and legs. In Prionus sexual activity 

 is very great, the male being attracted to 

 the female by her odor, and apparently, on the other hand, the males are attractive 

 to the females by the same means. Copulation, as observed in P. coriarius, lasts 

 scarcely two minutes. 



Fig. 371. — n 



Fig. 372. — Prionus laticollis and pupa. 



