August, '24] GLASER: REARING FLIES FOR EXPERIMENTAL WORK 
487 
necessary to feed them sugar or assimilable starch, together with,a solution of pro¬ 
teins or products of protein hydrolysis. In regard to the food for adult Stomoxys, the 
use of defibrinated cow or horse blood warmed to a temperature of 35-37°C. proved 
to be satisfactory for this form. This procedure facilitates the omission of living 
higher animals as a source of blood for the flies. A number of minor biological and 
life-history observations are included in the article. 
The article was written for investigators who use flies for disease, genetic, physio¬ 
logical or other biological researches. 
I. Introduction 
During the past four years the writer has reared large numbers of 
three species of flies for use in studying certain problems dealing with 
the relation of bacteria to these insects. These studies necessitated the 
development of simple, inexpensive and effective technical methods for 
rearing and handling large numbers of flies under experimental conditions 
and it is hoped that the present paper will give other investigators, 
interested in this phase of entomology, an opportunity to profit by or 
to elaborate upon and modify the experiences encountered. 
So many biologists have reared flies for use in dealing with disease, 
genetic, physiological and other researches that it is difficult to dis¬ 
tinguish between what is technically old and new. Much credit is due 
to such investigators as Howard, Jepson, Hewitt, Bacot, Graham- 
Smith, Bishopp and others, and the present paper does not in any way 
wish to minimize or overlook that which has been already accomplished. 
The methods of various investigators are scattered throughout a host of 
books, journals and bulletins which are not all readily accessible to any 
one individual. However, the writer feels that he has absorbed most of 
the important methods described, has modified these to meet other 
needs, and has introduced new links in the chain wherever this was 
considered advantageous. 
Musca domestica L., Stomoxys calcitrans L., and Lyperosia irritans 
Rob.-Desv. were the three species bred and handled. Certain proced¬ 
ures that are generally applicable to these will be first explained. This 
will be followed by separate descriptions of procedures applicable only 
to a single species. 
2. General Methods 
To start new cultures wild flies are caught around stables while 
sitting or feeding on horses and cattle, or while resting on the walls and 
sides of the stalls. They are best caught by means of small, straight 
phials such as shown in the illustration given on Plate 10, Figure 4. The 
open phial is moved very slowly and steadily towards the resting or 
