4 THE OAK 



injury having been reported in Massachusetts, Pennsylvania, Vir- 

 ginia, and Kansas to oak, elm, pear, and wistaria. The year follow- 

 ing pecans were attacked in Alabama and Mississippi, and hickory 

 and oak in Illinois. In 1910 the oak pruner attracted widespread 

 attention in the States of New York, Connecticut, and Massachusetts 

 and became the subject of many newspaper notices under the name 

 of the "gun-worm." 



LIFE HISTORY. 



From present knowledge of this species the following brief account 

 of its life history may be given: 



In the northern portion of the upper austral life zone the adult 

 appears in early summer. The mother beetle inserts an egg, usually 

 in one of the smaller twigs of a hving tree. The young larva hatching 

 therefrom first attacks the wood under the bark, following the grain 

 of the wood and packing its burrow with its sawdust-hke castings. 

 The larva, as it grows, bores toward the base, often consuming the 

 wood entirely around the limb and ejecting its castings through 

 holes which it makes in the bark. Later it follows the axis of the 

 twig, boring through the center and excavating a more or less oval 

 channel, sometimes for a distance of several inches. Dr. Asa Fitch « 

 has said that the larva is only about half grown when it severs the 

 lim b in which it is working, but it has more probably attained its 

 full growth at this time. He described this operation, recounting 

 at length how, with "consummate skill and seemingly superterrestrial 

 intelligence, he varies his proceedings to meet the circumstances of 

 his situation in each particular case." 



From Fitch's account it would seem that he imputed to this insect 

 a reasoning power, which enables it to modify its operations according 

 to conditions and to judge just how far the Umb should be cut off 

 to insure its ultimate amputation by the wind without endangering its 

 own safety. Whether guided by reason or by blind instinct, the 

 insect is actually enabled to accomplish this purpose. 



After cutting away the wood in such manner that the winds will in 

 time bring the limb to the ground, the contained larva retreats into its 

 burrow and plugs up the severed end with castings. Here it trans- 

 forms to pupa (fig. 1, c, f), sometimes late in the autumn and often 

 not until early spring, assuming the adult stage as early as November 

 and appearing abroad in June and throughout the summer until 

 September. 



A larva received from South Woodstock, Conn., transforrhed to 

 pupa May 3 and to adult May 21, having thus passed the pupal stage 

 in eighteen days, the average temperature having been about 74° F. 



o Fitch, Asa.— Fifth Report on Insects New York, pp. 797-804, 1859. 

 IClr. 130J 



