June-0ct.,i92i Bulletin of the Brooklyn Entomological Society 87 



pupae, emerged May 22, 192 1. The larvae were collected along 

 the margin of a stream near Hempstead, Long Island, N. Y., 

 during the latter part of April. 



ON THE GENUS MICROVELIA WESTWOOD (HEMIPTERA, 



VELIIDAE). 



By H. M. Parshley, Smith College, Northampton, Mass. 



(Contributions from the Department of Zoology, Smith College, 



No. 84.) 



A thorough monographic treatment of the American species of 

 Microvelia is a great desideratum, but this can hardly be accom- 

 plished until the type specimens of Champion and Uhler are care- 

 fully examined and the wingless phases of several species made 

 known. In fact, the complete elucidation of margindta Uhler, 

 robusta Uhler, and albonotata Champion will probably involve the 

 study of further collections from Central America and the West 

 Indies. Thus in connection with notes on two recently described 

 species, I think that it will be useful to oflfer some observations 

 on the genus, including a descriptive synopsis based largely on 

 new characters, by which most of the species reported from the 

 Eastern States may be readily distinguished in the apterous con- 

 dition. The macropterous forms, relatively very rare, may, as a 

 rule, be easily associated with their apterous phases by corre- 

 spondence in size and in antennal and genitalic characteristics. 



The structure of the thorax in the Gerridae and Veliidae is 

 curiously and diversely modified, and there is here an opportunity 

 for an extensive and thorough morphological investigation, al- 

 though Bergroth, Kirkaldy, and others have published something 

 on the subject. In Microvelia the apterous thorax is very pe- 

 culiar and has been much misunderstood. The pronotum is rela- 

 tively long on the median line and bears either a distinct trans- 

 verse linear impression (americana and borcalis) or one or two 

 rows of punctures. The mesonotum is much shorter than the 

 pronotum when visible, or it may be entirely concealed beneath 



