OUTLINES OF ENTOMOLOGY. 67 



cushioned beneath, and the third one bilobed. These beetles have the 

 power of producing a squeaking sound by rubbing the pro-thorax up 

 and down over the bases of the wing covers. This is done not only as 

 an expression of fear when captured, but for amusement or as a call to 

 their mates, and is termed Stridulation. The females have an oviposi- 

 tor that can be teles copically extended to a considerable length, in 

 order to place the eggs deep into holes or into the crevices of bark of 

 the trees in which the larvae feed. The colors of many species are 

 very bright, disposed in stripes or bands or in dotted patterns on a 

 plain ground. They are for the most part nocturnal, and conceal them- 

 selves carefully during the day. A few, however, are exceptional, and 

 may, at certain seasons, be found on flowers or enjoying the sunshine 

 on the trunks of trees. 



The larvae are all wood-borers, and many of them do great damage 

 to fruit and forest trees, and in vineyards. They are fleshy, white 

 cylindrical grubs, terminating bluntly behind, with all the joints sepa- 

 rated by deep incisions, and the first thoracic one much enlarged and 

 covered with a horny plate. The head is small and usually dark brown, 

 the greater part of it comprised in a pair of powerful jaws, capable of 

 cutting into the hardest wood. A few of these larvae have the usual 

 number of very small thoracic legs, but the majority have no legs at all, 

 and move up and down in their burrows by alternate contractions and 

 extensions of the body, and by means of the hunched segments. It is 

 a habit with some species to keep one end of the burrow open, through 

 which to push out the chips and castings, and their presence is often 

 betrayed by the little heaps of sawdust on the bark. The great ma- 

 jority, however, leave their castings in a compact mass behind them as 

 they proceed. Many of these larvae grow for two or three years, and a 

 few even longer. When ready for transformation they tunnel their 

 way to the surface, leaving a slight shell of the bark entire over the 

 place of exit. They then retreat to a safe distance and form a cell or 

 nest of wood fibers and castings, and here assume the pupae form. In 

 this stage they are soft and white, sometimes almost transparent, but 

 with each member of the future beetle clearly defined, and they have a 

 peculiar mummified appearance. At the end of two or three weeks the 

 membranous casings are slipped off and the perfect beetle, but in a 

 very soft and imperfectly colored condition, is disclosed. The insect 

 remains quiet in its cell for some time until all the parts are hardened, 

 after which it breaks through the slight door and enters upon the en- 

 joyments find business of its mature life. 



