492 
Saw-flies, Gall-flies, Ichneumons, 
worker digger-wasps, but each female makes a separate nest and provisions 
it by her own labor. The stored food consists of paralyzed or, more rarely, 
killed insects or spiders. “The nests may be of mud, and attached, for 
shelter, under leaves, rocks, or eaves of buildings, or may be burrows hol¬ 
lowed out in the ground, in trees, or in the stems of plants. The adult wasp 
lives upon fruit or nectar, but the young grub or larva must have animal 
food, and here the parent wasp shows a rigid conservatism, each species 
providing the sort of food that has been approved by its family for genera¬ 
tions, one taking flies, another bugs, and another beetles, caterpillars, grass¬ 
hoppers, crickets, locusts, spiders, cockroaches, aphids, or other creatures, 
as the case may be. 
“The solitary wasps mate shortly after leaving the nest, in the spring 
or summer. The males are irresponsible creatures, aiding little, if at all, 
Fig. 693.—A solitary wasp, Sphex occitanica, dragging a large wingless locustid 
(Ephippiger) to nest. (After Fabre; natural size.) 
in the care of the family. When the egg-laying time arrives the female 
secures her prey, which she either kills or paralyzes, places it in the nest, 
lays the egg upon it, and then, in most cases, closes the hole, and takes no 
further interest in it, going on to make new nests from day to day. In some 
genera the female maintains a longer connection with her offspring, not 
bringing all the provisions at once, but returning to feed the larva as it grows, 
and only leaving the nest permanently when the grub has spun its cocoon 
and becomes a pupa. 
“The egg develops in from one to three days into a footless maggot-like 
creature, which feeds upon the store provided for it, increasing rapidly in 
size, and entering the pupal stage in from three days to two weeks. In the 
cocoon it passes through its final metamorphosis, emerging as a perfect 
insect perhaps in two or three weeks, or, in many cases, after the winter 
months have passed and summer has come again. Probably no solitary 
