August, '16] PENNINGTON: RHOGAS TERMINALIS 401 



destroyed or made to stool excessively, the effect being the same as 

 produced by the work of the first generation of larvae in the earlier 

 wheat. 



A little later, but still early, infestation with /. grande affects the 

 height and size of the stem and the size of the head, usually making the 

 head small or very small. An early infestation of the highest or next 

 to highest joint affects the size of the head but does not appreciably 

 affect the height of the stem. Infestation of the third joint does not 

 seem to affect the plant as seriously as infestations higher or lower made 

 at approximately the same time. A very late infestation may occur 

 in one or even in two or three joints without seriously affecting the 

 stem or the head. 



NOTES ON RHOGAS TERMINALIS CRESS. 



{Hymenoptera, Braconidcv) 

 By W. E. Pennington, Scientific Assistant, Cereal and Forage Insect I nvestigations^ 



During the summer and fall of 1914 a very severe outbreak of Cir- 

 phis (Heliophila) unipuncta Haw. occurred at Hagerstown, Md. This 

 outbreak was carefully investigated by the force of the United States 

 Entomological Laboratory located at that point. Incidental to this 

 work several parasites of the insect were reared. This paper deals 

 with the data collected on one of these parasites, Rhogas terminalis 

 Cress. (Fig. 24a), and is presented at this time because it throws a 

 little additional light on the phenomenon of parthenogenesis. 



During late September, October and early November, a large number 

 of Cirphis unipuncta larvae were collected from the field. These larvae 

 were isolated in tin salve boxes two inches in diameter and three quarters 

 of an inch deep. As the larvae were isolated, they were arranged by 

 accession numbers which were marked with wax pencil on the top of 

 the box. The cages were stored in galvanized iron trays (PI. 30) , were 

 examined daily and fresh food supplied when necessary. In this way 

 the data was exact from the time of collection of the original host to 

 the completion of the experiment. From this material the initial 

 series of Rhogas terminalis for the following experiments was obtained. 



Table I gives the exact data relative to the emergence of the stock 

 material. 



The first note made at this Laboratory on Rhogas terminalis is dated 

 August 7, 1914, on which date J. A. Hyslop collected nine adult fe- 



'My thanks are due Mr. J. A. Hyslop for he'pful suggestions and assistance in pre- 

 paring the test and furnishing the illustrations; for the original adults making the 

 experiments possible, and for the courtesies of full cooperation. 



