26 WASP STUDIES AFIELD 



mate the future needs of space for her growing infant, its 

 food and the usual residue. 



We have already stated that this wasp stays with her 

 riest and daily brings in enough fresh flies to meet the 

 needs of the young one until it reaches maturity and pu- 

 pates. Just how many flies are brought in each day we 

 have never ascertained with accuracy, but we suspect that 

 the food supply varies with the needs of the infant. Also, 

 as we shall see later, this instinct of the mother for pro- 

 viding the daily food for her young is sometimes defective 

 and leads the mother to do various unprofitable things. 

 However, what she does is so wonderful that we shall not 

 presume to criticise her for occasional failures or erratic 

 behavior. 



When foraging and bringing in flies, they come and go 

 with surprising rapidity, often making three or four trips 

 in twenty minutes. They alight upon the nest with the fly 

 so well concealed under their bodies, clasped between the 

 middle legs, that we can hardly see it. They never waste 

 a second's time in searching to and fro for their nests, but 

 drop down from flight directly upon them every time. This 

 homing instinct is truly marvellous when we consider that 

 the bare area occupied by their colony is devoid of any ap- 

 parent landmarks by which they could locate their holes 

 amid the numerous holes of other insects. They work fast 

 and furiously from the instant they arrive, probably to 

 evade parasites, which soon shadow them if they are more 

 than a moment in their work, or to escape attack from their 

 sisters which are hot after them. In a fraction of a minute 

 they dig through the temporary closure of the burrow and 

 scramble in with the fly; in a few seconds they emerge 

 head first, turn around at the brink of the hole, and re- 

 enter at once. For an instant this performance seems 

 strange, but only for an instant; they enter just far enough 



