CO LEO PT ERA 



161 



the tarsi are apparently four-jointed, the fourth segment being very 

 small and hidden; the third segment of the tarsi is strongly 

 bilobed (Fig. 279). 



They are strong flyers and swift runners; but many of 

 them have the habit of remaining motionless on the limbs 

 of trees for long intervals, and when in this apparent trance 

 they suffer themselves to be picked up. But, when once 

 caught, many species make an indignant squeaking by 

 rubbing the prothorax and mesothorax together. 



The larvae are borers, living within the solid parts of 

 trees or shrubs, or beneath bark. They are white or yel- 

 lowish grubs. The body is soft, and tapers slightly 

 from head to tail (Fig. 280); the jaws are power- 

 ful, enabling these insects to bore into the hardest 

 wood. The larval state usually lasts two or three 

 years. The pupa state is passed within the bur- 

 row made by the larva ; frequently a chamber is 

 made by partitioning off a section of the burrow 

 with a plug of chips; but sometimes the larva 

 builds a ring of chips around itself just beneath the bark before 

 changing to a pupa. The pupal state is comparatively short, 

 lasting only a few days or weeks. 



Fig. 



Fig. 2 



THE PRIONIDS 



The larger of the long-horned beetles constitute a subfamily. They 

 are distinguished from other cerambycids by having the sides of the 

 prothorax prolonged outwards into a thin margin, which is more or less 

 toothed. The wing-covers are usually leathery in appearance, and of a 

 brownish or black color. The following are our best-known species. 



The broad-necked prionus, Prionus laticollis. — This is the largest of 

 our common species; but the individuals 

 vary from 1 to 2 inches in. length. It is of 

 a pitchy-black color, and of the form shown 

 in Figure 281. The antennae are twelve- 

 jointed in both sexes. The larva is a large, 

 fleshy grub, and infests the roots of grape, ap- 

 ple, poplar, and other trees. 



The tile-horned prionus, Prionus imbricornis, 

 is very similar to the preceding species but 

 can be distinguished at a glance by the form 

 of the antennae. In the antennae of the male 

 the number of segments varies from eighteen 

 to twenty, while in the female the number 

 varies from sixteen to seventeen. The popular 

 name refers to the fact that the segments 



of the antennae of the male overlap one another like the tiles on a 

 roof. The larva infests the roots of grape and pear, and also feeds upon 

 the roots of herbaceous plants. A closely related species, Prionus califor- 

 nicus, occurs on the Pacific Coast. The larva is from 2§ to 3 inches 

 long. 



