Field Studies of the Non-Social Wasps 41} 
the doorway. With a loud hum he would carry it back 
into the burrow, while she would go searching for an- 
other. I fell to wondering how he could get his own food 
under these circumstances, and watched closely to try 
to learn; after three days’ observation I am inclined to 
think that his spouse brings his food in to him. Often 
when the female came in, the male placed his mouth to 
hers for several seconds, in precisely the same manner 
as do the Polistes rubigenosis when they pass food from 
one to another.® 
None of the writers who find the males present in the 
nests of the various members of the genus Trypoxylon 
mention the behavior of mating which occurs, as I relate 
later, in 7. albopilosum, and which is much more pro- 
nounced in the species under present discussion, 7’. cla- 
_ vatum. Perhaps in the individuals discussed by Hart- 
man and the Peckhams, mating did not occur at the nest; 
it could hardly have been overlooked by observers so 
keen. If it does not occur in 7. rubrocinctum and 
T. teense, and occurs slightly or not at all in 
i¢ albopilosum, and very strongly in 7. clavatum, 
then one sees within the genus continued progress 
in this habit along evolutionary lines. If one could cor- 
relate this habit with the phylogenetic succession of the 
various species, one would get extremely interesting data 
Showing that habits as well as structure follow evolu- 
tionary lines. 
It is indeed pretty to see a female lightly carrying her 
gaily colored spider beneath her body, oscillating on the 
wing before the hole, where gleams the stolid face of her 
mate; she touches or vibrates his antennae with her own 
as if in delicate greeting, and flies back a little; the male 
follows her with his eyes, alertly cocking his head this 
5 To be published later. 
