24 
Some Solitary Wasps of Texas. 
in three cases near the last sealed end, in one case at the opposite 
end. 
One cell, the last one stored, I broke open to examine the con- 
dition of the caterpillars. I was especially anxious to see this, 
as I had once observed a specimen hang from a twig by one of 
the hind legs and chew the head of a cotton-worm, holding the 
caterpillar with her front and middle legs. I had often seen 
Microbembex' do this in exactly the same way, and as this 'species 
feeds her larva on any insect, dry or fresh, or on any part of an 
insect in almost any condition, I concluded that she sucks as much 
of the insects’ juices as she needs for her own sustenance and 
feeds the rest *to the larva. Charles Janet has likewise observed 
this with Vespa crabro , where the workers, when the colony is 
threatened with over-population, kill some of the larvae and pupae, 
suck their juices and feed the remainder, rolled up in balls, to 
the surviving larvae. In the case of Odynerus, I am pretty certain 
that she takes a caterpillar occasionally for her own delectation. 
I could draw quite near to the chewing individual and could see 
every movement, even of the mandibles, during the process. The 
condition of the caterpillars in the cell I opened, moreover, pointed 
to the fact that in chewing the caterpillar she was not preparing 
it for her offspring, but was satisfying her own hunger. Of the 
seven caterpillars found in the one cell ; all were in good condition, 
and four responded very perceptibly to stimulation, one of the 
latter moving spontaneously. All remained in practically the same 
condition until attacked by the growing larva. (Fig. 10.) 
I watched the growth of the larva until it was ready to spin 
its cocoon (September 26th). But as I had torn away a goodly 
part of the wall of the cell, it could not spin its cocoon all around 
and died. But the absence of the wall was not the chief cause of 
the pre-pupa’s death. When I returned to her on October 7th, 
I found the pupal skin completely covered with egg cases of a 
parasite. On close examination, these proved to contain myriads 
of mites in various stages of development. Such egg-cases I have 
often noticed on dead digger-wasp larvse, and they usually appear 
on the articulating membranes between the segments. 
From cell No. 4 the imago failed to emerge. In November, when 
I broke open the cell, I found the nearly mature wasplet dead. 
The cause of its death was easy to understand, as I found protruding 
from the sides of its abdomen a number of the egg-cases above 
mentioned. 
As regards the length of developmental periods, the above data 
