June, igi6 Bulletin of the Brooklyn Entomological Society 57 



distributed, since it is known from all the continents and nearly 

 all the islands in every zoological region. Be it pond, lake or 

 stream, it is always possible to secure them hiding among the 

 grasses or walking about the banks or stalking their game on the 

 green fields of duck-weed floating on some placid pool. This 

 genus also is dimorphic, the winged and wingless so notably dif- 

 ferent that they have frequently been taken for distinct species. 

 However, in the antennge we have such excellent characters that it 

 is always possible to bring together both forms of any one species 

 and to differentiate them from others, though closely related. 

 This character is largely employed in this key to the species of 

 Microvelia : ^~^ 



1 (2). Antennae comparatively short and stout, not exceeding length of 



head and thorax taken together; legs short and stout. 



M. atrata n. sp. 



2 (i). Antennse slender, of varying lengths. 



3 (4). Posterior tibise curved in male, straight in female; antennse short, 



not as long as head and thorax taken together ; apterous male, 

 long, slender, fusiform, female, short, broad, nearly orbiculate. 



M. h ore alls n. sp. 



4 (3). Posterior tibise straight in both sexes. 



5 (8). Posterior tarsi 3-jointed. 



6 (7). Antennal joint 3 longer than I, 4 subequal to 2 and 3 taken together ; 



joints 3 and 4 slender, equally stout and of the same diameter 

 throughout, 4 tapering at the end, antennse very long ; hemelytra 

 much marked with white M. alhonotata Champ. 



7 (6). Antennal joint 3 subequal to i, 4 shorter than 2 and 3 taken 



together, stouter than 3, fusiform; apterous form with dorsal 

 patches of blue-gray pile M. fontinalis n. sp. 



8 (5). Posterior tarsi 2-jointed; antennal joints i and 3 subequal, 4 much 



shorter than 2 and 3 taken together; apterous form with dorsal 

 patches of silvery white pile; winged form with unicolorous 

 hemelytra M. americana Uhler 



Microvelia americana Uhler, 1883, Stand. Nat. Hist., H : 274. 

 This species may be further separated from its relatives by the 

 fourth antennal joint longer than 3d, and i than 2, 2 being the 

 shortest ; 3 is the thinnest, the others of nearly equal diameter and 

 I sHghtly curved. The hind femora extend slightly beyond the 

 apex of the abdomen; the hind tibise are straight in both sexes, 

 and the hind tarsi two-jointed. Its life-history and habits have 

 been detailed before.* 



* 1910, Canadian Entomologist, XLII : 176-186. 



