hungerford: aquatic hemiptera. 117 



Hibernation. De Geer, 1778, said of Ge)-ris lacustris ". . . qu'il 

 la gange pour se garantir contre le froid." Our large G. remigis winters 

 as an adult hidden under some brush, logs or other shelter about the 

 water. 



Mating. De Geer also described the mating of Geri-^is. It begins in 

 early spring and continues through the season. 



Oviposition Dufour described the eggs of Gerris and their deposition. 

 They are laid on supports projecting from the water, and upon floating 

 objects as a rule beneath the water line. They are fastened by means of 

 water-proof glue. 



Incubation period. The waiter finds it to be about two weeks for this 

 species. 



Hatching. These bugs split the egg shell longitudinally and upon 

 hatching cast an embryonic molt which bears a shiny black "egg burster." 

 This lies on the cephalic end between the eyes. It is figured on Plate XV. 

 It has not ben noted heretofore by our American workers. Brocher has 

 mentioned it for the European form. This very transparent, flimsy, deli- 

 cate molt serves but the one purpose, that of aiding the bug to emerge. 

 Bueno describes it as "a diaphanous pellicle, very soft and hairy, so soft 

 that it does not retain its shape at all and is nearly invisible on the sur- 

 face of the water." Bueno considers it in the nature of an amnion. It 

 shows the 1-segmented tarsi, subapical claws, tibial combs on all the legs. 

 In case the bug hatches under water it swims about until it can attain 

 the surface. 



Behavior. The new bugs resemble little spiders and jump about with 

 the greatest alacrity. 



Number of Instars. There are five instars. Each instar lasts about 

 a week. 



Food Habits. Predaceous upon insects, such as midges, and Noto- 

 nectid njTnphs, coming to the surface from below, and Jassids or other 

 insects cast upon the water. About a drying pond they were feeding upon 

 snails left stranded upon the ooze. It sometimes required maneuvering 

 to pry the snail free from its support. 



Dr. C. F. Curtis Riley of Syracuse University gives splendid notes on 

 behavior. See Am. Nat., October to December, 1919. 



DESCRIPTION OF STAGES. 

 The Egg. 

 Shape "Long cylindrical, rounded at both ends and slightly concave 

 at micropylar end. There is one micropyle and the chorion is somewhat 

 thickened at this end." — Bueno. 



Color. White when first deposited, becoming amber as red eye spots 

 appear. 



Beuno has so recently published in an available periodical the descrip- 

 tions of the instars that they are not reproduced here. (See Ent. News, 

 May, 1917.) 



Gerris orba Stal. 

 This species has been the subject of behavior studies by Essenberg. 



