34 WASP STUDIES AFIELD 



females. On one occasion we saw a Bcmbix having much 

 difficulty in keeping out a sister wasp, whose home it seems 

 had been destroyed and who did not seem to care that it 

 was not her own hole which she was entering. This gives 

 us a possible clue to an explanation of the presence of six 

 wasps in one burrow ; perhaps they had returned to the field 

 at twilight, found themselves homeless after the ball-game, 

 and had found it convenient to crowd into the same opening 

 for a night's shelter. 



The BembLv do not seem to be so discriminating in re- 

 gard to the choice of their prey as are some other wasps. 

 So long as they can pick up flies, they do not seem to be 

 particular about the variety. We have found in their bur- 

 rows: Lucilia caesar Linn. [F. Knab], Spogostylum anale 

 Say [F. Knab], Sarcophaga sp. [F. Knab], Sparnopolius 

 brevirostris Macq. [F. Knab] house flies, stable flies and 

 many more species which could not conveniently be 

 identified. 



The amount of food consumed by one of these youthful 

 gourmands is quite astonishing. One which we brought up 

 from infancy by hand consumed seventy-nine house-flies 

 before it spun its cocoon. Another consumed the forty-nine 

 house-flies and one large stable fly which had been given it, 

 and then attempted to spin its cocoon. In the smooth tin 

 box it made only a silky carpet (fig. 6 a). After that, 

 thirty-six more house-flies were introduced, and it devoured 

 twenty-six of them in spite of the fact that it had already 

 begun to spin. How many flies the mother provides for a 

 single larva has never been ascertained; but after its pupa- 

 tion there is usually from a teaspoonful to a tablespoonful 

 of legs and wings remaining. Occasionally we find that 

 a mother has devotedly brought in more flies than the larva 

 has been able to consume; but some of our work leads us 

 to suspect that these gluttonous young are more often will- 



