142 
Psyche 
[December 
and in figure eights just an inch or two above the mass of 
multi-colored refuse. As one singles out certain individuals, 
however, one soon realizes that frequently they describe 
circles within still larger circles. Each fly circles about hori- 
zontally in an area of ten or twelve inches with occasional 
breaks by an insect into another’s circle; all this gives the 
assemblage a placid and slow-moving appearance. Often a 
fly will leave the dance to rest on a tin-can or on a glass bottle, 
many of which stud the heap. Sometimes one will go in pur- 
suit of another and quarreling occurs. When the quarrel 
culminates mating usually takes place. Mating is consum- 
mated while they are on the wing but the pair soon settle 
down amid the garbage to rest, remaining in copulo for 10 or 
15 minutes. So intent are they in this affair that the object 
upon which they repose may be carried for a long distance 
without arousing them. 
When one examines a mated pair closely one finds that the 
larger insect, the female, is invariably on top of the smaller 
one, the male. Both heads are close together and during the 
process the female caresses the face and eyes of the male 
with her front legs. This behavior is very much like that of 
a fond mother petting her child. It is quite evident that the 
male enjoys this procedure, for he responds by licking her 
leg with his proboscis. Often his mouth parts will actually 
reach out to meet her leg, but sometimes he holds them alert 
in attentive readiness. One pair behaved this way for 15 
minutes while I held the bottle upon which they rested in my 
hand. 
The flies, singly or in copula, never rest on the moist por- 
tions of the garbage but always upon some hard dry object 
in the mass. Sometimes they rest on the grass-stems 
near their stamping grounds. They have never been seen to 
feed on garbage and I have never seen them lay eggs there, 
although I have watched carefully to detect both activities. 
However, oviposition must occur on objects nearby and also 
very soon after mating, for on one occasion when a mated 
pair separated in my hand, the female deposited about a 
hundred eggs in less than ten minutes. 
