20 
Some Solitary Wasps of Texas. 
usually consists in a given species of wasps of a particular kind 
of insect, one capturing only caterpillars, others only spiders, flies, 
bugs, beetles or other insects as the case may be. 
The solitary wasps mate in the spring or summer. The female 
alone engages in the work of rearing the family. When the egg- 
laying time arrives, she digs or builds a nest, secures her prey, which 
she either kills outright or merely paralyzes, stores it in her nest 
and lays her eggs among the store of provisions. In most cases, 
the food is carried home once for all, tbe nest is closed over the egg 
and the mother flies away and digs a nest in another place, paying 
no further attention to the old nest. In a few genera, the mother 
maintains a further connection with her offspring, feeding the 
growing larva from day to day until it has spun its cocoon. 
The egg of a solitary wasp hatches in one to three days into a 
maggot-like larva, which feeds on its store of provisions and grows 
for two weeks or less, when it spins its cocoon and becomes a pupa. 
In this state it remains two or three weeks in summer before 
emerging as the perfect insect; or if cold weather comes on, the 
insect remains quiescent in the pupal state until the following 
spring. It is probable that no adult solitary wasp survives the 
winter. 
The solitary wasp emerges from its cocoon in possession of all 
the instincts of its ancestors. It is, moreover, born into the world 
alone, and there is no chance for imitation of its fellows, as is the 
case with social bees and wasps. Wonderful as these instincts are, 
they are not so perfect as was supposed, for observation has shown 
that they are to a high degree variable, and often show remarkable 
adaptation to circumstances, which is called by some, intelligence. 
The study of the habits of animals had been too little studied to 
bring out the fact of variability, for it is apparent that, to detect 
variations, be they in morphological characters or in actions, the 
type of structure or the normal action of the animals must first 
be determined. The present paper is a contribution in this direc- 
tion, as it embodies observations of some twenty-eight species of 
Texas solitary wasps. 
The principal students of the habits of solitary wasps, in fact, 
the only ones that have studied them comparatively, are M. J. H. 
Fabre of France and Mr. G-. W. and Mrs. E. Gr. Peckham of 'Mil- 
waukee, Wis. M. Fabre has given us the results of his keen and 
careful observations in his interesting and delightful papers, “Souve- 
nirs Entomologiques.” The Peckhams published their equally in- 
teresting results with sound deductions on the instincts of animals 
