204 
Psyche 
[September 
species can be kept in confined quarters in great numbers 
and the individuals will not fight or molest one another as 
long as they are in good condition. 
If the food is too heavy to be taken away, the incurva 
feed on the prey in situ. Where possible pieces are pulled 
off and these are taken off and surreptitiously eaten, upon 
which the beetle returns again for another morsel. Thus 
it is a common sight to the experimenter to see six to 
ten incurva tugging and biting at such large prey as 
the larger Muscidae ( Lucilia , Calliphora) , feeding on the 
fly, with the beetles distributed in a circle about the victim, 
each beetle with a certain section of the carcass. Under 
these conditions when a beetle leaves its place and attempts 
to dislodge a neighbor, the latter bites at the intruder and 
usually drives it away. 
The incurva usually attack the mouth-parts of their prey 
first (Fig. 1) and these are sucked or licked for the moisture 
obtained. Before attacking such a fly, the beetle will often 
circle it several times, biting at the sclerites and wings in 
passing and then invariably settle on the moist mouth 
region or the membranous joints between segments of the 
legs and body sclertes. However, if a wound is first made 
in the fly, this is attacked as readily as the mouth-parts. 
Even more readily is a dead or disabled worker of the 
host ant, ulkei , attacked. The behavior is essentially the 
same, the beetles showing a preference for the mouth parts 
glistening with regurgitated fluid. If the head of the ant 
is crushed a drop of fluid is forced on the mouth-parts and 
this is rapidly devoured by the beetles, often one on one 
of the ant’s mandibles, and a second on the other side of the 
head, the two biting at each other when they are too close 
or driving away other beetles from this region. Occasion- 
ally the gaster of the ant is licked, possible for the oily 
secretion, and the antennae and leg joints, or wounds are 
attacked. 
The queens of the guest ant, Solenopsis molesta , living 
with Formica ulkei, are attacked by the latter when pos- 
sible (Park T. Loc. cit.) and Tachyura feeds on molesta 
also. Here the molesta queen is devoured in the same way 
