OF WASHINGTON, VOLUME XV, 1913. 25 



that the genus Belvosia as now known is based upon structural 

 characters which are quite variable. Fortunately, that indescrib- 

 able something which we call "habitus" is strongly in evidence 

 in the genotype B. fasciata. But the question immediately arises; 

 what about those genera and species of Muscoidea based almost 

 entirely upon chaetotactic characters and where habitus is weak? 



In a series of 130 specimens of Winthemia quadripustulata reared 

 from larvae and pupae of Laphygma frugiperda collected mainly on 

 the grounds of the Department of Agriculture, Washington, D. C., 

 during the month of September 1912, 9 specimens or about 7 

 per cent were found which cannot be properly placed specifically 

 by the existing tables. Two group characters are used in these 

 tables, one being the number of dorso central bristles, the other, 

 the number of sterno pleurals. No variation was found in the 

 number or arrangement of the former. In the latter, however, 

 the number and also the arrangement was found to be variable 

 to the extent noted above. Seven of the variants are males, five 

 of them large specimens. The two females are smaller than aver- 

 age size. In the males the arrangement of the sterno pleurals 

 giving the left side first is as follows: 



In the females 



It will be seen from the foregoing that the variation is both 

 symmetrical and otherwise in the series and that the supernumer- 

 ary bristle may be placed either at the anterior or posterior corner 

 of the sterno pleura. Thus the stability of this character in 

 Winthemia is evidently far more absolute. There is also apparent 

 in this series a considerable variation in the comparative lengths 

 of the second and third antennal joints and in the width of the 

 latter. 



In justice to Mr. J. D. Tothill it should be stated here that an 

 examination of the cotype material of his Winthemia fumiferance 

 shows the species to be obviously distinct from W. quadripustulata, 

 notwithstanding the above noted failure of the sterno pleural 

 characters. 



There is one other character used in connection with the Tachi- 

 nidse which needs careful investigation, namely, the hairiness of 

 the eyes. In a series of 24 specimens, 12 males and 12 females, 

 of Myiophasia cenia Wied. reared as parasites of Chalcodermus 

 ceneus Boh. by G. G. Ainslie of the U. S. Bureau of Entomology, 

 at Clemson College, South Carolina, the males have hairy eyes 



