4io Phylum Arthropoda 



The larvae must be fed their favorite aphid hosts and may be reared 

 in almost any type of cage. When they are full grown they must be 

 placed in a moist environment exposed to light. Glass tumblers or jars 

 covered with cheesecloth, half full of moist sand, the surface of which 

 is covered with leaves and sticks, are the most convenient types of pupal 

 cages. The sand must be kept moist and the jars placed near windows 

 or electric light. Sunshine does not seem to be necessary. 



CULTURE OF THE DRONE FLY, ERISTALIS TENAX* 



William L. Dolley, Jr., C. C. Hassett, W. B. Bowen, George Phillies, 



University of Buffalo 



ERISTALIS tenax has been shown to be especially valuable for the 

 study of its reactions to light, because it is uniformly positive and 

 orients accurately in light, is of large size, and is hardy in captivity. It 

 is also valuable for many other types of work. 



Previous attempts to rear it have proved unsuccessful. This organism 

 has now been successfully reared for over 3 years. In December 1931, 

 a female collected in the open the previous month laid eggs, and from 

 these a strain has been reared continuously since. 



The flies are kept in wire cages, 15x15x15 cm., containing watch 

 glasses filled with cheesecloth moistened with tap water. In these cages 

 are also small wooden feeding troughs filled with a mixture consisting of 

 equal parts of dry poppy, Eschscholtzia calif ornica, pollen and dry pow- 

 dered cane sugar. On this food the flies live perfectly and lay many 

 fertile eggs. 



The cages are kept before a laboratory window but are not exposed 

 to the direct rays of the sun. 



The eggs are collected and placed on human feces in a vessel also 

 containing moist earth. Fresh feces are added daily. The larvae pupate 

 in the soil. 



At a temperature of between 20 and 25 C, a typical female began 

 laying eggs 10 days after emergence and laid about 3,000 eggs in about 

 60 days. The eggs hatch about 36 hours after they are laid. The dura- 

 tion of the larval and pupal stages is about 2 weeks and 8 days, respec- 

 tively, at about 22 ° C. Oviposition has been observed at various tem- 

 peratures between 20.5 and 30.5 ° C. 



The pollen may be purchased from Knapp and Knapp Pollen Gardens, 

 North Hollywood, California, or it may be raised. The poppy blossoms 

 are collected each day. The anthers are clipped off with scissors and 

 dried in the sun for 12 hours. The pollen, separated from the dried an- 

 thers by means of a sieve with a fine mesh, is placed in a desiccator 



♦Reprinted with slight changes by the senior author from Science 78:313, 1933. 



