184 Annals Entomological Society of America [Vol. IV r 



Finally some black cloth screens were placed on the ground under 

 infested cherry trees and the larvae dropped readily to the 

 cloth. They were most active about 4 o'clock in the afternoon. 

 Eighteen larvae dropped to cloth screens between 2.15 and 4 

 p. m., June 29, according to notes made by Mr. T. M. McCall. 



The Cocoon and Pupa Stage. The small earthen cells 

 of the larvae were found commonly in the summer within an 

 inch of the surface of the soil. Probably they go deeper for 

 the winter. 



In the summer it was about 20 days after the slugs entered 

 the soil that the adults emerged. In 19 cases the average time 

 was 19.9 days, with a range of 15 to 23 days. 



The Adult. The sawflies were most numerous early in the 

 morning, although they were found in small numbers at other 

 times in the day. In July the sawflies all appeared at about the 

 same time, but in the spring the emergence was spread over a 

 much longer time. 



NATURAL ENEMIES. 



Egg Parasites. The most common egg parasite was 

 Pentarthron minutum Riley, kindly determined for me by Mr. 

 A. A. Girault. It is a very tiny, yellow-brown species, which 

 has often been reared from the eggs of a number of common 

 insects. 



At Ames this species was reared abundantly in 1909, but 

 not at all in 1910. A few individuals were reared from eggs 

 collected at Reinbeck, Iowa, in August, 1910. 



From the first brood eggs the parasites emerged from June 

 28 to July 20; from the second brood eggs, from August 11 to 

 August 20th. 



The eggs affected by this parasite turn black, and of course 

 fail to hatch. Two or three individuals were reared from a 

 single egg. 



Professor Peck in his original account mentions what is 

 doubtless this same species and gives figures of it. After look- 

 ing over the account I came to the conclusion that Peck had 

 reared the same parasite in Massachusetts in 1798 that I 

 reared in Iowa a hundred years later. Mr. A. A. Girault, to 

 whom I referred a copy of this account, corroborated my opinion 

 that Peck's parasites were most probably Pentarthron minutum. 



