488 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
feeding fly until approximately p 2 inch from the insect’s dorsal surface 
when a sudden, quick movement will span the remaining distance and 
capture the quarry. By using one phial as a storing bottle and another 
as a catching one, several flies may be transferred to the storing phial. 
This is accomplished by taking advantage of the flies’ positive helio¬ 
tropic reponses. The means used for transferring living insects from one 
phial or bottle to another is too well known to deserve further comment. 
If two or three dozen phials are used, aprpoximately one hundred flies 
may be caught during the course of an hour, provided they are plentiful. 
This method of catching the insects is simpler and preferable to the use 
of nets and traps; injury to the flies is avoided, one can nearly always 
instantly determine which species or sex is being caught, and with a 
little practice one can obtain a larger number of the desired flies in a 
shorter while than in any other way known. The phials may also be 
washed and sterilized should this be desirable. 
On starting a new culture early in the spring when the adults are 
first appearing and the gonads are still undeveloped, it is necessary to 
capture both sexes and feed them about two weeks in order to produce a 
sufficient number of fertile eggs. Later in the season only females with 
swollen abdomens should be taken. These are usually fertile and ready 
for oviposition on a favorable medium. Indeed, very often gravid females 
will oviposit in the collecting bottles. 
The newly qaptured flies may now be transferred to the breeding 
jar. A type of jar devised, which proved highly satisfactory, is shown 
on Plate 9, Figure 1. It consists of an ordinary battery jar with a wooden 
top which is covered with a No. 20 mesh (400 meshes to the square 
inch), copper wire gauze. The center of the top is perforated by a hole 
one inch in diameter and just large enough to insert the opening of a 
collecting phial. In making the hole, the one-inch diameter auger is 
replaced by a three-fourth-inch diameter one when three-quarters of the 
distance has been bored. This forms a narrow shelf upon which the 
collecting phial may rest. The reverse side of the top is shown on 
Plate 9, Figure 2. It will be seen that the entire top is cut from one 
piece of wood. The grooves for fitting the top to the battery jar are 
also shown at the junction of the central support and the rim of the 
top. Since the diameter of the tops and jars vary slightly it is difficult 
to obtain a close fit. This can be corrected by making a paper collar as 
shown in Figure 1. About one-fourth to one-third of a jar is filled with 
the larval medium (horse manure, fermenting straw, or cow dung) 
packed loosely with a wooden stick and moistened slightly with water. 
