OF WASHINGTON, VOLUME XIX, 1917 89 



June 8. By Entomological Ranger F. B. Herbert July 7, 1915, 

 a female flying in the forest at the Pyramid Ranger Station, 

 Calif; July 17, 1915, at Fallen Leaf, Calif., a female crawling on a 

 dead white fir (Abies concolor); and .May 5, 1916, at Placerville, 

 Calif., a female on the stump of a yellow pine (Pinus ponderosa) 

 treated in February, 1915, in the control work against the western 

 pine beetle (Dendroctonus brevicomis). 



Probably the most interesting point connected with the life 

 history of Oryssus is what becomes of the long external ovipositor 

 of the pupa upon transformation to the adult. The actual 

 transformation was not observed so this is a point to be deter- 

 mined by future study. Another point to be determined is the 

 exact length of the life cycle. The larvae of the genus Buprestis 

 upon which the Oryssus is parasitic live for several years in the 

 wood of the host plant. So far the Oryssus larvae have been 

 found only with the large larvae of the Buprestis. Whether they 

 are internal feeders when small in the small larvae of the Bu- 

 prestis or whether they attack only the large larvae are points 

 for future determination. 



The specimens upon which these observations were made will 

 be turned over to Mr. S. A. Rohwer for taxonomic study. As the 

 larvae appear quite different from the typical horntail (Siricoided) 

 larva and the habits are quite different, the systematic position of 

 Oryssus in the classification of the Hymenoptera may be changed. 



IDIOGASTRA, A NEW SUBORDER OF HYMENOPTERA WITH 

 NOTES ON THE IMMATURE STAGES OF ORYSSUS. 



BY S. A. ROHWER, Specialist in Forest Hymenoptera, AXD I{. A. Crsn\i.\\, 



Entomological Assistant. 



Bureau of Entomology, Washington, D. C. 



The summary by Rohwer of the literature dealing with the 

 habits of the oryssoids published in 1912 (Proc. U. S. Nat. Mus., 

 vol. 43, p. 141), shows the conflicting suppositions explaining the 

 habits of the members of this interesting group. The impor- 

 tance of the discover}- of the larva of Oryssus ocddentalis and its 

 habits by Mr. H. E. Burke are very manifest and have called 

 forth the remarks on the position of the group offered below. 



While the authors do not believe that the biology or any char- 

 acters especially developed by unusual habits should be made the 

 primary reason for systematic groups we do believe that biology 

 offers a good index to affinities and gives valuable suggestions as to 



