Tue RIBBED PINE-BoRER 371 
The front coxae are conical and prominent; their cavities are open and 
are angulated externally. The front tibia has no oblique groove on the 
inner margin. The hind tibial spurs are terminal. The prosternum pro- 
jects prominently between the coxae. 
The elytra are gradually narrowed from about the middle to the apex. 
The intervals between the longitudinal ridges are coarsely and sparsely 
punctate. 
The chief character that usually distinguishes this beetle is he extensive 
projection of the prosternum between the prominent fore coxae. Its 
general pubescence mottled with grayish brown and black, together with 
the short antennae, usually readily identifies this species. 
The sexes are of the same general uniform coloration, but usually differ 
in two distinguishing characters: (1) the femaie (Plate VIII, 2) is 
about 3 millimeters longer and proportionally larger than. the male 
(Plate VIII, 1); and (2) the tip of the abdomen is exposed in the female, 
while in the male it is entirely concealed by the elytra. The insects vary 
in length from 12 to 18 millimeters. Those found in small trees with 
thin bark, and hence scanty food, are usually smaller than those found in 
larger trees. 
During the warm days of early spring the beetles become active in their 
pupal cells, and gradually begin gnawing through the bark to the exterior. 
The time of emergence is usually during the last week in April, but this 
may vary a week or more, depending on weather conditions. The beetles 
are active as soon as they emerge, and fly readily if disturbed. 
Since these insects winter as adults the reproductive organs have had 
sufficient time to mature. In the spring the female’s ovaries are full of 
large eggs. Copulation occurs as soon as the adults emerge. It occurs 
frequently, and a pair may remain in copula for several hours. In fact, 
during the first few days after emergence, this process may be repeated 
again and again at different times. One pair was taken in copula as 
late as the last week in June. 
Although this beetle is a pine insect, and although it feeds on the bark 
after becoming an adult, it ceases to feed on pines after emerging. It 
then becomes a pollen feeder, feeding on such flowers as the dogwood — 
a habit which it has in common with many of its near relatives among 
the cerambycids, 
