Il8 ENTOMOLOGICAL NEWS. [March, '09 



continuous with the next at the base. So far as I have been 

 able to determine there is no connection between the whorls of 

 different enlargements. The segments also bear long hairs, 

 usually one large hair below each loop and a smaller one al- 

 ternate with the loops. In addition, rows of very fine hairs 

 encircle the segments. The genitalia are shown in figure ig. 

 The wings are about twice as long as broad and clothed with 

 fine scattered hairs. They also bear a fringe of long hairs along 

 the hind margins (Fig. iw). 



This pest is going to be a difficult one to control and it may 

 be that the main dependence will have to be placed upon para- 

 sites which evidently increase as the season advances and kill 

 enough of the Contarinia to enable a late crop of Kaffir corn 

 to mature its seed. If this proves true it may become neces- 

 sary to plant late for a crop of seed. Of course, where the corn 

 is desired for soiling purposes or for green feed, early planting 

 is all right. 



There is a second crop of Kaffir corn on the station grounds 

 just maturing its seed, and the uninfested heads in this field 

 averages in an extensive count, about ninety-one per cent. Nine 

 per cent, of the heads were either badly or only slightly infested. 



The number of adult Contarinia and of Aprostocetus bred 

 from some of these infested heads is also interesting as throw- 

 ing some light on the work of the parasite, perhaps. It would 

 depend, altogether, whether there were one or more parasites 

 to each host. The ratio of the emerging adults of parasite 

 and host in these late heads is as six of the former to one of the 

 latter. 



At the time this paper was written, I was not aware that 

 anyone had investigated the work of this pest. Later I find 

 that Dr. C. R. Ball in 1907 came to the same conclusions re- 

 garding the sterility of sorghum and published a note on Dip- 

 losis sorghicola in Circular 13, Bureau Plant Industry, and 

 again in Science Vol. XXVII. , No. 681, pages 114-115, Jan., 

 1908. 



