REPORT OP COMMITTEE ON PUBLICATION 191 



Description. 



Egg. The eggs of the grape root-worm are small, glossy, semi-trans- 

 lucent, yellow bodies. The means of 416 eggs were 1.05 mm. (.041 inch) 

 in length and .315 mm. (.012 inch) in diameter. They are cylindrical in form 

 with the ends hemispherical. The stresses produced by the bark, under 

 which they are laid, generally cause the major axis of the egg to be more or 

 less curved. 



Larva. When full grown the larvae vary in length being 8 to 10 mm. 

 (.3 to .4 inch). They resemble somewhat the common white grub but are 

 much broader in proportion to their length. The spiracles are brown, 

 nine being visible on each side of the body. The head and thoracic shield 

 are yellowish-brown. 



Pupa. The pupae are slightly shorter than the larvae and are cream 

 colored. Hooklike processes are found on the distal ends of the femora and 

 the posterior parts of the body. A number of hairs and setae are found on 

 the body, those on the head and posterior parts of the body serving to sup- 

 port the pupa in its cell. 



Adult. The adult beetle is about 6 mm. (.25 inch) in length and all por- 

 tions of the body have a nearly uniform brown chitin which is densely 

 covered with short gray hairs. The usual color of the adults is gray, 

 due to the abundance of hair. There is considerable variation in individuals 

 as regards color, some specimens having the upper parts of the body and 

 elytra brown caused, in some instances, by the shortness of this hair, in 

 others, by the lack of hair. It seems that the activities of some individuals 

 rub off many of these hairs on the back but all individuals have the under 

 sides of their bodies covered with gray hairs. This is nature's way of pro- 

 tecting them from their enemies for when the beetles drop to the ground 

 and lie motionless this color causes them to resemble the soil and thus they 

 escape being seen by their enemies. The pits bearing the hair are not 

 arranged in any definite pattern but there are larger pits which do not bear 

 hair and these are arranged in rows which run lengthwise and cause the 

 insects to have a finely striated appearance. 



The clypeus and mandibles are shining black the former having a num- 

 ber of yellow setae. Each Antenna consists of eleven segments being 

 a light brown with many hairs and setae. The legs are brown with the 

 tarsi slightly darker. 



Seasonal History. 



Emergence. During a normal year, the beetles emerge the latter part of 

 June and the early part of July. We expect to find the first adults emerging 

 near the 25th of June, on gravel soils, but the majority do not appear until 

 almost a week later and certain straggling individuals may not come forth 

 until nearly three weeks later. The time will be a week to ten days later 

 on the heavier soils. The adults have been found as early as June 18th and 

 during late seasons the first ones were not found on gravel soil until July 

 5th. The occurrence of rains may influence the emergence especially on 

 the heavy soils where the ground has formed a hard crust for here the 

 beetles are imprisoned and cannot emerge until the rain loosens the soil 

 sufficiently for them to dig their way out. 



