208 THE UNIVERSITY SCIENCE BULLETIN. 



latter species he said he kept confined for a long time, and that they lay 

 their eggs toward the last of April "en les collant centre des brins de 

 plantes aquatiques." Regimbart, 1875, said that A'^. cimicoides buried its 

 eggs in plant tissues. 



Genus PELOCORIS Stal. 



The members of this genus and its European relative Naucoris of 

 literature, are better known than those of Amhrysus. Frisch, 1727, under 

 "Von der breiteren Wasser Wanze" says it is predatory and can chirp. 

 Roesel, 1746, says that "Die breit leibige schwarz braune Wasser Wanze 

 mit dem gelb eingefassten hinter leib und derselben Fortpflanzung" had 

 an egg like the back-swimmer, only more rounded, and that the adults in 

 August overwintered. De Geer noted their food and nocturnal flights. 

 More recently we have Kirkaldy's notes on IlycoHs cimicoides and Bueno's 

 history of Pelocoris femorata. 



Hibernation. As far as known all of these bugs winter as adults 

 hidden in mud and trash. Uhler says that Pelocoris femorata hibernates 

 at the bottom of pools and ponds, in places where it can find some depth 

 of muck, and especially where reeds or water-plants remain rooted 

 through the winter. 



Oviposition Roesel, 1746, Dufour, 1833, and Kirkaldy, 1905, describe 

 the eggs of the European form cim,icoides as placing its eggs upon stems. 

 Regembart, 1775, said it inserted them in tissues of plants. In sup- 

 port of Regembart, Wesenberg-Lund in "Fortpflanzungsverhaltnisse; Paa- 

 rung und Eiablage der Suss wasserensekten" says: "In May, 1895, I 

 found numerous eggs in the air spaces of leaves." Out in nature they 

 were in old plant parts. From the ovipositor he thinks it is not likely 

 that it just lays them on the plants. 



The American P. femorata, Uhler, 1884, says, glues its eggs to the sub- 

 merged leaves and sprays of plants. Bueno, 1903, also finds this to be the 

 case. He says, "The majority have been found attached axially to the 

 stems or leaves of Ceratophyllum and secured to them by a glue in which 

 the ovum is set and which surrounds slender stem or leaf to a variable 

 extent." 



Incubation. Bueno has found the egg stage to last from 22 to 27 days. 

 This was in early June. 



Number of Nym.phal Instars: Five. 



Food Habits. The writer has fed them many different kinds of insects. 

 They will also eat snails. Bueno fed his bugs one fly apiece each day. 



Behavior. These bugs like the dense cover accorded by water plants. 

 In a series of "holes" in an intermittent creek bed near Coldwater, 

 Kan., Naucoris carolinensis was taken in great numbers. These pools 

 were spring-fed, and overgrown with a "water moss" (Nitella). This 

 collection was made July 28, by the party under Mr. Beamer's direction. 

 The description of the waters is taken from the collector's field notes. 



"The bottom was clay and sand, covered with 3 or 4 inches of soft, 

 slimy mud, and above this was a great mass of moss. (Nitella.) We 

 could not run the net through into it very far, but had good success 

 pushing it into it as far as possible and then lifting and shaking the 



