ENEMIES OF PLANT-LICE 107 



were all dead. It was with difficulty that these delicate 

 organisms could be removed, and if the minute wasp-egg was 

 among them we failed to notice it. Just above this was 

 another cell, also disconnected, containing a full-grown 

 larva, but the food-supply had been exhausted. Still further 

 up, in line with the gallery and nearer to the opening, were 

 two cells, evidently older, since in them the pupal cases were 

 already spun. 



Hence we see here that the wasp probably uses one tun- 

 nel throughout its life, and that it digs a little channel turn- 

 ing sharply downward at the end, fills the end of it with 

 prey and an egg, seals it up, thus forming a cell, and con- 

 tinues the burrow further into the earth in such a way that 

 the little cells are always dropped beneath the gallery. Thus, 

 as we progress inward, we find the young in earlier and 

 earlier stages of development. As the season advanced these 

 galleries and the row of subjoined cells became more nearly 

 complete, while the mother continued, at least in several 

 marked holes, to work in the same nest week after week. 



Until the middle of October they were industriously at 

 work on every day that was warm enough for them to ven- 

 ture out, and even on November 3 several dared to come 

 forth as if attempting to continue this work. 



No notes on the behavior of this species have been pub- 

 lished. A moment's comparison with the ways of allied 

 species may give the reader a more comprehensive idea of 

 the ways of this group. 



Westwood 2 says that Diodontus gracilis and D. corniger 

 provide aphids for food for their progeny, carrying them 

 in the mouth to their cells in the holes in posts. Morley 3 

 finds D. tristis V. der Lind. flying to nests in sand banks. 



2 Introduction to Modern Classification of Insects 2; 195. 1840. 



3 Entom. 31 : 14. 1898. 



