Tkansactions Texas Academy of Science. 
39 
sitic flies. Indeed, I once noticed two grey Muscids with reddish 
abdomens follow a wasp with her caterpillar for a great distance. 
Their persistence greatly agitated Microbembex , and she several 
times left the caterpillar and ponnced upon one or the other fly 
and threw it to the ground. The blow was, however, not serious, 
for the fly continued without fear as before. Why the wasp did 
not kill the interlopers on the spot, I can not understand. Fabre, as 
well as the Peckhams, wonder at the laxness of Bembex in her treat- 
ment of parasitic flies which she keeps driving away instead of 
killing them once for all. This would be easy for her to do, if she 
were so inclined; a single sting, applied as it is to another fly th^t 
is to serve as food, would forever rid her of one of these trouble- 
some intruders. Both the French and the American observers fail 
to offer an explanation for the phenomenon. It may be that the 
sting is not used on other occasions than the capture of prey, just 
as is the case of the queen domestic bee the sting is never drawn 
except in mortal combat with a rival queen. Since it is always 
certain species of parasitic flies that are in attendance upon the 
wasps, it may be through mere familiarity with the flies, and the 
presence of those so near to the nest, that they are so much tolerated. 
For the flies are in every way treated like other wasps of the same 
species. I have seen a Bembex knock down another Bembex or a 
Microbembex and have even seen them clinch as if earnestly en- 
gaged in fighting, but they never drew their stings. 
Notwithstanding the half hearted efforts of Microbembex to rid 
herself of her enemies, these follow her to her nest. Having ar- 
rived at the nest the wasp opens it, grasps the caterpillar with her 
hind legs and drags it inside, walking in head foremost. Ammo - 
phila , it will be remembered, backs into the nest and pulls her cater- 
pillar in backwards. 
(2) Another common object brought in by Microbembex, was 
the leg of a grasshopper. On several occasions I saw this carried 
along in the same way that the caterpillar was carried. Once an 
ant was making away with the leg of a grasshopper which it had 
probably purloined from the Microbembex herself. The wasp many 
times picked up the leg but the ant would not let go, but forced 
the wasp to drop it, until the latter gave up the fight. 
(3) Twelve small queens of ants. These had been dead for 
some time. They all probably came from the same spot, as they 
were brought home in quick succession. 1 The nest was left open 
while the queens were brought in, which is an exceptional thing for 
Microbembex to do. 
