168 



nut they enter the ground where they remain until the succeed- 

 ing summer. 



THE COMMON ACOEN WEEVIL, Balaninus quercus Horn. 



This is the largest of the weevils attacking acorns. In size, 

 it is similar to the hickorynut weevil but in color it more nearly 

 resembles the larger chestnut weevil. The spots on the back are 

 smaller than in the latter species, however, and are not so bright 

 and conspicuous. The snout is very slender and is curved at 

 the point. In the female, it is nearly half an inch in length, or, 

 about a fifth longer than the body. In the male, it is about two- 

 thirds as long as the body. The pygidium, or last abdominal 

 segment, of the male is deeply concave with the concavity smooth 

 and shining and surrounded by a rim of silken hairs. This pec- 

 liar character enables the species to be separated very readily 

 from all other members of the genus. 



This species seems to attack only the acorns of the biennial 

 oaks and in my collecting has always been found more abundant 

 on red oak than on any other tree. The acorns which it attacks 

 are late in maturing and the beetles are correspondingly late in 

 appearing. My earliest record for adults is July 30th, when 

 four newly transformed beetles were found in the ground under 

 a red oak tree. My first specimen from the tree was taken Au- 

 gust 23rd. During September and until the middle of October 

 the beetles are abundant on biennial oaks. Egg laying beings 

 about the first of September and continues very active for four 

 or five weeks. 



In ovipositing the beetle pierces the 

 acorn to the full length of her long snout 

 and then makes many branches . leading off 

 at an acute angle from the first puncture. 

 Eggs are placed at the extremity of only a 

 part of the branches and these are deposited 

 at intervals during the long and tedious task 

 ^ excava t m g- After the eggs are all in 

 place the beetle deposits a small mass of ex- 



/^7 r? /? 



LJ Is U^ 



