INVESTIGATION OE LIFE HISTORY. 29 



An examination of this table shows that larvae hatching late in 

 June transformed much more rapidly than those noted in Table 

 IV, the difference in the total average length of time being 12 J days. 

 Similar records based on a few experiments have been secured from 

 larvae that hatched at the laboratory late in July or during the first 

 few days in August. The length of time spent in the larval stages 

 was longer than the time required for the larvae hatching in June. 

 This is partly due to the difficulty of furnishing an ample food supply 

 in August. 



Time of Appearance of the Larva. 



The date of the first appearance of the larva of this species in the 

 field, of course, differs from year to year, depending on the season, 

 and in colonies that have been liberated larvae are seldom found 

 as soon as the first ones hatch and begin feeding. The records of 

 this investigation are rather fragmentary because of the relatively 

 small number of adults that have been liberated in field colonies 

 since the work began, and owing to the difficulty of making frequent 

 examinations of any given colony and searching thoroughly enough 

 to find the small larvae. The earliest field records, however, are as 

 follows: 1907, July 17; 1908, June 29; 1909, July 7; 1910, June 27. 

 It should be stated that the first larvae found in 1907 were nearly 

 full grown, which explains partially the reason for their being found 

 so late in July, although the season was not so early as that of the 

 two following years. The latest records which we have of finding 

 larvae in the field are as follows: 1907, August 7; 1908, July 8; 1909, 

 August 3; 1910, August 2. In the laboratory, where food was more 

 abundant in early June and during the month of August than in the 

 field, it has been possible to rear larvae over a longer period of time. 

 Aside from the food problem it has been possible to control to some 

 extent temperature and moisture conditions, so that the time during 

 which feeding experiments have been carried on has been prolonged. 



Habits of the Larva. 



Larvae of this species secure food by searching for the caterpillars 

 and pupae of various lepidopterous insects. Undoubtedly some of 

 those attacked are found on the surface of the ground or beneath 

 leaves or litter, where they have sought shelter either for protection or 

 pupation. The larvae of this species, however, in addition to feeding 

 in such situations are able to climb trees and devour their prey upon 

 the trunks or branches. To this extent they may be considered 

 arboreal in habit, although they are seldom found in any great 

 quantities on trees which have smooth bark, as it is quite necessary 

 for them to travel over uneven surfaces in order to secure a sure 



