1975] 
Gwynne and Evans — Larropsis 
281 
encountered a cricket near the sand surface, where it was able to 
escape by leaping away from the wasp. Even though searching 
Larropsis females are usually followed by satellite flies, they normally 
successfully avoid these parasites by capturing their prey under- 
ground. Senotainia species will not enter burrows and will larvi- 
posit only on exposed prey outside the burrow (Evans and West 
Eberhard, 1970, p. 61). This was revealed when a satellite fly was 
observed to follow a L. chilopsidis female as she entered a camel 
cricket burrow. Although the fly appeared to show much interest in 
the burrow mouth she did not enter but perched nearby for about 
20 minutes (observation D). A satellite fly was successful in larvi- 
positing on the prey in the single observation (B) where the female 
had stung the prey outside the burrow. In this case the cricket had 
presumably escaped from the wasp and had been chased, subdued, 
and eventually dragged back to its burrow. 
Both of the species studied do not dig their own nests but utilize 
burrows of their prey, thus conserving the energy required to dig a 
nest. Use of pre-existing cavities for nesting is common in the sub- 
family (Larrinae) to which Larropsis belongs, having been reported 
in such genera as Liris (Steiner, 1962), Lyroda (Evans, 1964), 
Ancistromma (Evans, 1958a), and Larra (Williams, 1913, 1928; 
Smith, 1935). Ancistromma distincta females do some digging, but 
usually take advantage o ; f natural cavities in the rocky soil of their 
nesting habitat. Species of Larra evidently locate their mole cricket 
prey in their burrows using olfactory cues, then attack the prey and 
lay their egg in the host’s burrow, much in the manner of Larropsis 
species. However, the position in which the egg is laid is quite dif- 
ferent in the two genera, Larra spp. laying the egg just back of the 
base of a hind leg, Larropsis spp. between the front and middle legs. 
These different egg positions are undoubtedly adaptive and are re- 
lated to the fact that mole crickets dig with their front legs, sand 
treader camel crickets with their hind legs. Mole crickets attacked 
by Larra recoved quickly from paralysis and resume normal activities 
until killed by the developing wasp larva; thus it is to the advantage 
of the wasp larva that it be coiled posteriorly and not in a position 
to interfere with digging by the host. Sand treader camel crickets 
attacked by Larropsis spp. also recover from paralysis within a few 
hours and appear to be able to resume normal activities. One cricket, 
which we dug up some 15 hours after it was stung (observation C, 
L. chilopsidis) , leaped from the excavated cell, and it was only when 
we captured the insect and found the wasp’s egg that we were able 
to be sure it was the prey. However, we have no actual evidence 
that the crickets are able to dig their way out of the cells into which 
they are packed by the wasps. 
