Junes, i9i6 Hessimi-Fly PavasUes 381 



addition to the downward pressure exerted on it. The female always 

 took a position heading up the stem in ovipositing. The whole process 

 generally took five minutes or more. 



CONCLUSION 



The writer's experiments and observations have all led to the inference 

 that only one specimen of any of the three species studied ever matures 

 in a single Hessian-fly puparium. In every instance where more than 

 one egg or larva was placed on the same host or in the same cell, one 

 survived and the rest were killed by that one, or starved to death. This 

 was true whether the two or more larvae were of the same or different 

 species.* 



1 For correct figures of the adults of all three of the species treated in this paper, see U. S. Dept. Agr. 

 Fanners' Bui. 640. (Webster, F. M. The Hessian fly. 20 p., 17 fig. 1915.) 



