496 



Phylum Arthropoda 



they were easily recaptured. The females copulated readily in captivity 

 but, failing this, reproduced parthenogenetically. In some cases, the 

 adult parasites were fed with small drops of diluted honey in a separate 

 dish so that the aphids would not become entangled in the food. This 

 was not necessary when material was abundant as they can live without 

 food for 5 days. The above methods were employed with the following 

 Aphidiinae and hosts: 



PARASITE 



APHID HOSTS 



PLANT 



Bibliography 



Wheeler, Esther W. 1923. Some braconids parasitic on Aphids and their life- 

 history. Ann. Ent. Soc. Amer. 16:1. 



Family 



ICHNEUMONIDAE 



HYMENOPTEROUS PARASITES OF GYRINIDAE* 



ADULTS of several species of Hemiteles were obtained by rearing 

 l from cocoons of Gyrinus which were placed in small vials with 

 cellucotton stoppers. Later in the season the parasites were reared suc- 

 cessfully in small paraffin cells made by sinking a heated nail-head into 

 a paraffin block. The parasitized host larva was removed from its pupal 

 case and placed in the paraffin cell. Then a small cover glass was heated 

 and placed on the cell, a small air hole being made by means of a 

 "minute nadel." By this method the development of the insects, 

 which feed externally upon the host larvae, could be observed carefully 

 under the binocular. 



Oviposition was first observed in the laboratory with females which 

 had been reared from host cocoons and kept isolated. Newly con- 

 structed host cocoons were placed in isolation vials with adult females 

 to permit oviposition. Eggs deposited by these females developed into 

 adults, demonstrating that these insects can reproduce parthenogeneti- 

 cally. Later in the season the two sexes were mated. 



♦Abstracted from an article in Ann. Ent. Soc. Amer. 26:76, 1933, by F. Gray 

 Butcher, N. Dakota College of Agriculture. 



