hungerford: aquatic hemiptera. 157 



Ranatra annulipes Stal. 1854. 



Of. Vet. Akad. Forh., XI, p. 241. 



B. Biology of Nepid^. 



General Notes. These water bugs are to be taken by raking the mud 

 and trash out of the water. They swim but little, spending most of their 

 time motionlessly awaiting the close approach of some unwary creature. 

 Their raptorial fore legs are usually set before them, and are capable 

 of striking forth with lightning rapidity. Once the insect or other little 

 animal is caught in the vice-like grip there is little chance of escape. 

 The broad flat Nejm is likely to be found in the mud or leaves at the 

 edge of the pool, while the Ranatras may be taken in trash in waters of 

 various depth. The flat, dirty, roughened coat of the former, and the 

 long, slender shape of the latter give these bugs an aggressive resem- 

 blance to mud and tangled trash respectively. When going through open 

 water, the legs are moved alternately, making the gait, as Kirkaldy sug- 

 gests, a paddle rather than a swim. 



Genus NEPA Linn. 



The one species in this country has a general distribution east of 

 the Mississippi river. The writer has taken it at Ithaca, N. Y. 



Habitat. It is a mud-loving bug, and usually found in raking out 

 mud and trash near the water's edge. Bueno (Can. Ent., XXXVII) says 

 N. apiculata is found in shallow water, not much over two or three 

 inches deep, concealed in the mud or in situations where grasses grow 

 out of water clinging together. 



Hibernation. It winters as an adult, and has been taken in winter 

 collecting. 



Mating. Roesel, 1755, said that Nepa remains paired two days and 

 nights. Hewitt, 1906, figures and describes the mating of Nepa cinerea 



Oviposition. The peculiar eggs of these bugs bear seven filaments.* 

 They are inserted in the tissues of decaying plants. These were figured 

 many, many years ago by Swammerdam, 1737. Roesel, 1755, stated that 

 they were dropped to the bottom. Geoffrey said the eggs were laid in 

 the twigs of Scirpus or some other aquatic plant. Recently we have 

 Wesenberg-Lund's statement, 1915, that the species of his country lays 

 its eggs at night and he figures them in moss plants. Brocher, 1913, says 

 their Nepa lays in April and can be found in October with eggs com- 

 pletely formed ready to lay. The number of filaments he says are vari- 

 able. "Authors have indicated seven, but the eggs which I have had 

 the occasion to observe had eight or nine. The eggs are fixed in the 

 skin of plants in or floating at the surface, only the filaments resting 

 exteriorly." 



Hatching. Brocher says at the moment of hatching the anterior ex- 

 tremity of the eggs is opened like a lid of a box and the larva comes 

 forth. He figures the hatching process giving 6 figures. The larva 



* Our N. apieulata lays eggs bearing 11 filaments. 



