106 WASP STUDIES AFIELD 



carrying aphids a$ usual. No males were present, and 

 the sun-dance seemed quite forgotten. The dance is no 

 doubt a sign of their having just emerged, so probably the 

 date we have recorded for that event might be accepted as 

 approximately the date of the first appearance of this 

 species. 



iFic. 28. The burrow and cells of Xylocelia metathoracicus. Enlarged. 



We succeeded at last in tracing one hole to its terminus. 

 The opening and gallery were about three mm. in diameter. 

 The channel was tortuous, owing partly to the rocky condi- 

 tion of the soil, and its total length was less than four inches. 

 At the bottom of the gallery (fig. 28) were four aphids. 

 Doubtless the mother was carrying in prey when we in- 

 truded. A short distance to one side in the earth was a 

 little cell, sealed off ; this was completely packed with forty- 

 eight aphids, all of the one species, Aphis setariae. They 



