THE PAINTED HICKORY BORER 195 



If placed at the plugged end of the cell, it quickly moves itself back to 

 the opposite end by means of the spines on the thorax and abdomen. 



Transformation to adults 



In the laboratory the pupa began to show the characteristic markings 

 of the adult by the middle of October. However, they did not transform 

 to adults until the following February. In the field, the winter is passed 

 in the pupal stage. All of the pupae under observation at the insectary 

 were killed by the extremely cold weather during the winter of 1917, 

 so that records on the transformation to the adult stage were not obtained. 

 Likewise it was found that pupae in infested material in the field had 

 also been killed by the unusually cold winter of that year. This agrees 

 with the observations of Craighead (1918) and other workers on forest 

 insects, who also reported a great mortality among wood-boring insects, 

 due to the severe cold. 



However, pupae obtained from infested material, late in the winter 

 of 1919, transformed to adults during that spring and emerged. The exact 

 time of transformation from pupae to adults was not determined. 



SEASONAL HISTORY 



The adult insects emerge during May and June, and sometimes, during 

 the first few days of July, depending on the season. They feed on the 

 pollen of Crataegus and probably on that of other flowers. The elongate- 

 oval, whitish eggs are deposited in crevices or under flakes of the bark. 

 These hatch in from six to ten days, and the young larvae, burrowing 

 thru the bark, then construct an irregular, U-shaped burrow, which grooves 

 both the bark and the solid wood, and is tightly packed with the sawdust- 

 like borings. The larvae become mature in from ten to twelve weeks, 

 at the end of which time they construct the pupal cell, first opening a 

 hole to the exterior thru which the borings are to be expelled. When 

 the pupal cell is hollowed out, the larva retreats into it, plugs up the 

 entrance with splinters and sawdust, and enters into a prepupal stage 

 lasting from twenty-five to sixty-three days. The transformation to 

 pupae begins about the middle of September, and by November 12, all 

 are in the pupal stage. In Ithaca, the winter is therefore spent as pupae. 

 The transformation to the adult beetles takes place in the spring. 



NATURAL ENEMIES 



The hickory borer has very few natural enemies. Riley (1874) 

 mentioned finding the larva of an Elaterid (Hemirhipus fascicularis 

 Fabricius) following the burrows of the hickory borer in hickory and 



