February, '16] BILSING: PECAN TWIG GIRDLER 111 



off limbs, more than an inch in diameter. The Hmbs, however, are 

 usually 7 to 10 mm. in diameter. 



Food Plants 



This insect is not at all choice in the selection of a tree upon which it 

 intends to girdle hmbs. 



Pecan, persimmon and the various species of elm seem to be preferred 

 to the others. Pear trees are also often severely pruned. From the 

 observations we have made it would appear that most any kind of a 

 plant may be selected if necessity demands it. The following is a 

 list of trees on which the insect has been taken: Pecan, persimmon, 

 elm, hackberry, mesquite, rose, sweet locust, water oak, post oak, live 

 oak, hickory, maple, pear, and peach. 



Egg-Laying Habits 

 The limb is first cut off although this habit varies to some extent 

 and occasionally some of the eggs are deposited before the limb is 

 entirely severed. In nearly all cases the adult stands with head down- 

 ward in cutting off the hmb. After severing the limb the adult begins 

 to oviposit. The eggs are laid at the base of the leaf buds and usually 

 one egg is deposited at a place, but this also varies and sometimes two 

 and in rare cases 3 or 4 eggs are deposited at one leaf bud. The number 

 of eggs deposited in a single hmb varies but is usually from 8 to 12. 

 The female is usually accompanied by the male but the girdhng is 

 done entirely by the female. Before depositing the egg she makes an 

 incision with the mandibles at the point where the egg is to be depos- 

 ited. After this incision is made some little time is taken to hollow out 

 a place between the bark and the limb in which to place the egg. This 

 hollowing out process is done by the ovipositor. After this is com- 

 pleted the egg is deposited and the opening is sealed by a black gluey- 

 hke substance which is discharged from the ovipositor. Next the 

 female makes a great number of small transverse incisions below the 

 point where the egg is deposited with her mandibles. This is done so 

 the bark in drying will raise like a blister and not crush the egg. Dur- 

 ing the period in which she is depositing the eggs the female often 

 ascends to the end of the branch and begins feeding. In nearly all 

 cases observed the female as well as the male fed entirely on the tender 

 wood at the base of the leaf buds at the extremity of the branch. This 

 feeding habit is not confined to the branches on which she is ovipos- 

 iting but she may feed on other branches as well. The method of 

 girdhng varies but in most cases the cut is made entirely around the 

 hmb. The limb is seldom entirely severed but a small portion of the 

 center is left intact. The weight of the limb, especially if the tree is 



