360 Forty- SIXTH Report on the State Museum 



the name of the Oak-pruner, Elaphidion putator. In his Report 3, pi. 2, 

 fig. 2, is a figure of the beetle. It is also noticed and figured in Dr. 

 Harris' Insects Injurious to Yegetation, 1862, p. 98, figs. 47-8-9. Dr. 

 Packard, in his Guide to the Study of Insects, 1869, on p. 496, 

 represents the larva and pupa, but the accompanying figure should not 

 be accepted for the imago. Excellent figures of E. parallelam in the 

 larva and beetle, with enlargements of portions of the same, and of the 

 pupa in a section of the excised branch, after Riley, may be found in 

 Dr. LeBaron's Fourth Report on the Insects of Illinois. [These are 

 given in Figure 29.] 



In speculating upon the reason for the cutting off of the twigs by the 

 larva. Dr. Fitch writes as follows: "As the worm is to remain in the 

 limb through the winter, it appears to foresee that, from being wounded, 

 as it is, it will perish and become too dry if it remains elevated in the 

 air; it therefore drops it to the earth, where, lying among the fallen 

 leaves and buried beneath the winter's snow, it remains moist and 

 adapted for the development of the insect within it." 



Although secreted within the central portion of the branch, the 

 larva does not enjoy immunity from its foes. Woodpeckers may dis- 

 cover its retreat while still upon the tree, and artfully extract the 

 favorite tid-bit. After the larviie drop to the ground their burrows are 

 probed, and they are extracted by many of the smaller birds, or eaten 

 hj burrowing insects. Certain it is that many of the excised twigs, 

 when examined, will be found without the larva within them. 



The branches sent by Mr. Thomas were received about the 20th 

 of July, when the larvae were already at least half -grown: the eggs 

 liad probably been deposited in early June. One of the twigs, four- 

 tenths of an inch in diameter, had been cut off at three inches above 

 w^here the burrow entered from the tAvig that nurtured the young larva. 

 A section of a larger branch, over half an inch in diameter, shows the 

 entrance of two larvie from lateral twigs, one inch and three -fourths 

 apart. In this the burrowing is still goinsj on, as is shown by a large 

 quantity of small, round, hard, whitish grains of excrement which are 

 being thrown out. [Of several branches of red oak received from 

 McGregor, Iowa, — in one, measuring one inch in diameter, the cutting 

 was unusually thorough, passing entirely through the wood and into 

 the bark, leaving only a thin outer film of the bark, so that the branch 

 would break off by its own weight. Another section of a larger 

 branch, measuring one inch and one-half, shows one-fourth of its 

 plane uneaten, so that the action of the wind was necessary to its 

 breaking and separation.] 



