Tachinidae 411 



over calcium chloride for from 24 to 48 hours. It is then kept in dark- 

 ness in glass bottles in which air has been replaced by nitrogen or carbon 

 dioxide. Poppy pollen rapidly deteriorates on exposure to light, air, 

 or moisture. 



Since these methods of culturing it are comparatively simple, Eristalis 

 tenax is now available for work throughout the year. 



Family 



TACHINIDAE 



METHODS USED IN REARING LESCHENAULTIA EXUL 

 Henry A. Bess, Ohio State University 



ATACHINID fly, Leschenaultia exul, deposits microtype eggs upon 

 foliage fed upon by its host larvae. Rearings of this parasite were 

 made from larvae of Malacosoma americana (tent caterpillars) which 

 had ingested foliage on which females of Leschenaultia exul had been 

 induced to deposit eggs. 



The oviposition chambers used in the laboratory were glass-covered 

 wooden boxes 5.9 x 7.9 x 3.9 inches. The boxes were supplied with 

 block cane sugar, honey water on a piece of sponge, and cherry foliage, 

 with the basal ends of the twigs in a bottle of water. Care was taken 

 to keep the food and foliage fresh at all times. To obtain oviposition 

 in the field flies were confined in bags made of cheesecloth and cellophane. 

 These bags were about 5 feet in length and 16 inches in diameter. Only 

 the middle third of each bag was cellophane and the cloth ends were open 

 so that the bag could be slipped over a branch and tied in place. 



Oviposition was not obtained readily from freshly collected flies with- 

 out either cutting the leaves or placing host larvae within the containers. 

 The effect produced by host larvae feeding on the leaves would be similar 

 to cutting the leaves with shears. 



Parasitism was obtained by feeding pieces of foliage on which eggs had 

 been deposited to individual host larvae in metal boxes 2 inches in diam- 

 eter and 1% inches in depth. The turgidity of the foliage was maintained 

 by placing a piece of moistened paper toweling in the bottom of each 

 box. In many instances to insure early ingestion of the eggs the host 

 larvae were starved for 1 day previous to their entry into the experiment. 



Each day the caterpillars which had eaten the infected foliage were 

 removed from the individual metal boxes (except a number for special 

 study) and placed in one gallon glass jars which contained about two 

 inches of loam soil. Over the soil was placed a piece of paper toweling 

 which was removed with the frass daily. The jars were covered with 

 paper toweling held in place with a rubber band. By moistening 



