224 ON THE HEMIPTERA-HETEROPTERA OF GRENADA. [Mar. 6, 



estate and at Woburn, in March, April, and August, in spring- 

 water. These insects vary in the width and proportion of the 

 body, as well as in the extent of black on the tips of the wing- 

 coverts, just as we find to be the case in our smaller species of 

 Notonecta. This we know to be the case from frequent observa- 

 tion of the various forms taken in sexual connection. 



Plea, Leach. 



Plea striola, Pieber. 



Plea striola, Pieber, Entom. Monogr. p. 18, pi. 2. figs. 1-3. 



Several specimens of this small insect were found at Woburn, 

 August 30, on a sluggish stream, in a flat open country near sea- 

 level. This species is sometimes common in ponds of stagnant 

 water in most parts of the United States ; it inhabits also Mexico, 

 Cuba, Central America, and California. 



CORISID.E. 



Cobjsa, Geoff. 



1. Corisa cuBiE, Guerin. 



Corisa cubce, Guerin, Sagra's Hist. Cuba, Ins. p. 422. 



Two specimens, both males, were secured at Woburn, August 

 30, in a sluggish stream in the open flat country near sea-level. 

 This species is also now known from Plorida, Texas, and Mexico, 

 besides the island of Cuba. 



2. Corisa reticulata, Guerin. 



Corisa reticulata, Guerin, Sagra's Hist. Cuba, Ins. p. 423. 



More than a dozen specimens, including both sexes, were found 

 at St. George's and on the Mount Gay estate, in August and 

 September, in pools of fresh water, and also in brackish water. 

 A specimen from the Caliveny estate was found near the sea, 

 in a pool of fresh water. 



Sigara, Pabr. 



Sigara socialis, B.-White. 



Sigara socialis, B.-White, Trans. Ent. Soc. Loudon, 1879, p. 274. 



Nearly two dozen specimens of this species, including some 

 varieties in size and colour, were collected on most parts of the 

 island. At Balthazar it was found June 11, flying at sunset 

 after a heavy rain. On the Mount Gay and Telescope estates it 

 was taken in August from spring-water ; but at Woburn it was 

 more common, August 30, in a sluggish stream in the open 

 country near sea-level. This species occurs also in Mexico and 

 California, but it has not yet been taken in the eastern part of the 

 United States. 



