hungerford: aquatic hemiptera. 237 



the observations do not represent the usual feeding behavior, 

 which is given elsewhere, 



GENERAL HABITS OF CORIXIDS. 



Buchanan White, 1873, gives us perhaps the best general 

 account of the behavior of the Corixids. Johannes Hagemann, 

 1910, published an extended dissertation on the anatomy and 

 behavior of these insects. 



White pictures them so well that his words are here re- 

 peated : 



"The adult Corixa in swimming uses only the posterioi- legs. These 

 legs are also used for cleaning the elytra. In doing this the animal 

 uses one or both legs, brushing the pronotum, elytra, the underside of 

 the hind body, and the long hairs at its end. To assist perhaps in this 

 cleaning process, the inside of the hind tibia and the base of the first 

 joint of the hind tarsus are provided with what may be called the comb 

 or rake hairs. These are shorter and stiffer than the swimming hairs, 

 and are widened and flattened at the extremity, being in fact somewhat 

 oar-shaped, and truncate at the apex, which has five long teeth. These 

 teeth are admirably adapted to rake out any particles of foreign matter 

 which may have lodged in the fine rostrations with which the pronotum 

 and elytra of many species are sculptured. The species which have 

 no rostrations (such as Macrocorixa) are, equally with the rostrate 

 species, provided with rake hairs. These rake hairs are not present in 

 the young. The middle legs are used for standing on, the long claws 

 clasping stones or plants, and the body of the animal remaining at 

 some distance from the object rested on. The animal can also walk in 

 a kind of way with these legs, its progress being at the same time 

 assisted by short, jei'king strokes of the hind legs through the water. 

 When at rest and not clasping anything with the claws, the animal rises 

 to the surface of the water. The front legs or palje are used for feeding. 

 When in action they are brought rapidly and alternately to the rostrum. 

 In action they hang downward, their tips approaching each other; in 

 swimming they lie backward along the sternum." 



A glance at the photograph of the living bugs under water 

 shown on plate III will indicate their characteristic poise. 

 The boatmen spend most of their time in the shallow waters, 

 where they rest upon the bottom, their mottlings of yellow 

 and brown rendering them inconspicuous midst the flocculent 

 bottom ooze. It might here be mentioned that the May fly 

 nymph, living in the same situation, is similarly camouflaged. 

 Now and then the boatmen swim quickly to the surface, ex- 

 pose the thorax for a brief moment, and dart below again. 

 In turbid waters the presence of the boatmen is determined 

 only by the brief flashing of their bodies as they take air 

 at the surface. 



