296 ENTOMOLOGICAL NEWS. [July, '17 



strong flier, and I have found it in ocean beach drift in July, 

 on the shores of Long Island 3 . Gerris lacustris, so Griffini 

 says 4 , touches the water at times with the abdomen, which it 

 rests on the surface. I have not seen marginatus do this. He 

 also states that it has been observed to be attracted bv mirrors. 



Gerris marginatus begins to oviposit early in the spring; 

 the eggs hatch out in ten days to two weeks, depending on the 

 temperature. After five molts it reaches the adult in from 5 

 to 6 weeks. Unlike its larger congener rcmigis, it is a dweller 

 in still waters by preference. Here at times it gathers in 

 large numbers. In strong winds it hugs the shore, particularly 

 if it blows that way. From early March to late November it 

 may be found busy about its domestic affairs. The height of 

 its abundance is between April and September. In early April 

 they have been noticed mating; by May 20 to 26 adults and 

 nymphs in one or two stages are seen together, and so through 

 June and July, when they are found in several stages together. 

 Its food is the same as that of rcmigis, except that being small- 

 er it is not able to overcome quite such large insects. I have 

 seen marginatus trying to capture Notonecta undulata which 

 had flown to a pond and was on the surface struggling to 

 submerge. The Gerris avoided reprisals by jumping up from 

 the surface. On the other hand, it is one of the few water- 

 bugs that fall a prey to frogs, and is, in fact, the only one I 

 have seen recorded. 



Its structure is characteristic of the genus ; in fact, belong- 

 ing in the typical subgenus, it closely approaches the generic 

 and subgeneric type, Gerris lacustris Linne. In common with 

 this species, marginatus rejoices in the phenomenon of ptery- 

 gopolymorphism. Kirkaldy says 5 : "lacustris has provided 

 me with more variations at least six than any other species. 

 It is noteworthy that in the brachypterous forms, the two ab- 

 breviated elytra are not always equal in length and develop- 



3 igi5. Ent. News xxvi: 277. 

 4 i8g4. Gli Insetti Acquaioli p. 39, 



Entomologist, xxxii : No. 432: p. 109. 



