138 NEW YORK STATE MUSEUM 



to our knowledge of these interesting forms. His paper gives a very 

 good idea of the inter-relations existing between the various species. His 

 studies show that there are 21 primary parasites of this pest and three 

 others that probably hold the same relationship. He obtained 14 hyper- 

 parasites and 1 1 species were reared from dead chrysalids or cocoon masses. 

 He states that in Washington D. C, Pimpla i n q ui s i to r Say and 

 Chalcis ovata Say [fig. 18, 19] are the two species most effective in con- 

 trolling this- pest, and that large numbers of the former insect hibernate as 

 larvae within the cocoons of the host, while in no instance was the latter 

 parasite reared from cocoons of Hemerocampa taken the previous winter. 

 He has also shown that when hymenopterous parasites are comparatively 

 scarce, certain tachinids may destroy large numbers of this pest, the more 

 important being Tachina mella Walk., Frontina frenchii Will, 

 and Euphorocera claripennis Macq. Besides those mentioned 

 above, Dr Howard gives the following as primary parasites of this species : 

 Pimpla conquisitor Sa)-, Pimpla annulipes Say, A m o r p h o t a 



r g y i a e How., ]\I e t e o r u s communis Cres., M e t e o r u s h y p h a n- 

 triae Riley, Limneria sp., Limneria valida Cres., T heron i a 

 fulvescens Brulle, Apanteles delicatus How., A pan teles 

 hyphantriae Riley, Apanteles parorgyiae Ashm., P t e r o- 

 m a 1 u s c u p r o i d e u s How., Cratotechus orgyiae Fitch, T e 1 e- 

 nomus orgyiae Fitch, Frontina aletiae Riley, Exorista 

 g r i s e o m i c a n s \' . d. \\^ and W i n t h e m i a 4 - p u s t u 1 a t a Fabr. At 

 Washington these parasites became so abundant that in the autumn of 1S95 

 about go% of the larvae were destroyed. In addition to the above named 

 parasites, Dr Howard records that Ichneumon subcyaneus Cres., 



1 c h n e u m one o e r u 1 e u s Cres. and Allocota thyridopterigis 

 Riley were all observed investigating recently formed Hemerocampa cocoons 

 and were apparently about to oviposit. The last, he states, is parasitic 

 upon Pimpla. 



In his study of these parasites Dr Howard found that the conditions 

 were not uniform in all parts of the city of Washington, the parasitism being 



