hungerford: aquatic hemiptera. 211 



distinguishable from the face, the opening to the mouth being on the 

 front of the so-called beak. The front tarsi are also peculiar, being 

 1-segmented, flattened and fringed with strong bristles. They are spoon- 

 shaped, or palaeform. The middle legs are long, slender, and end in 

 two long claws. The hind legs are flattened and fringed for swimming. 

 Historical Review. "Corixa" means bug, and is a fitting name for 

 these water bugs, for they have a buggy smell. They have been known 

 by this name since Geoff'rey, 1762. Borner, 1904, in a study of the mouth 

 parts of this group, separated these bugs off as a separate suborder, 

 Sandaliorrhyncha. The other suborders he called Auchenorrhycha 

 (Homoptera), Heteroptera and Conorrliyiicha. Bueno even gives them 

 ordinal rank, but Reuter reduces the Sandaliorrhy^ncha to a series under 

 the Heteroptera. 



Key to Genera. Doctor Abbott, of Washington University, has been 

 working for several years upon a world monograph of these bugs. He 

 expected to complete the systematic part two years ago, but the inter- 

 ruptions of the times have kept him from so doing. It is a most difficult 

 group, and it is to be hoped he can give the workers a practical means 

 to determine their material.* For the present the writer gives a tenta- 

 tive key to the genera. He knows of too much synonomy to waste time 

 on specific keys to the large genus Arctocorixia, which contains some fifty 

 species, for instance. Only the males are keyed out satisfactorily. The 

 females look much alike. 



KEY TO GENERA OF CORIXID^. 



Males. 



A. Scutellum covered by pronotum only at the anterior margin, Pro- 

 notum roundly emarginate behind. Tenagobia Bergroth. 



AA. Scutellum covered (except sometimes at posterior angle) by pro- 

 notum. 



B. Strigil absent. Pronotum and tegima more or less rastrate. 

 Conspicuous black spot usually present on hind tarsi. 



Callicorixa White. 

 BB. Strigil present. 



C. Strigil on left side. Pronotum and tegmina smooth, 

 shining, asymmetry on left side. Corixa Geoff. 



CC. Strigil on right side. 



D. Head of male sharply acumiate. Asymmetry right. 

 Strigil small. Ramphocorixa Abbott. 



DD. Head of male normal. 



E. Hind wings usually aborted. Palar pegs in 

 two series, or one crowded row. 



Palmocorixa Abbott. 



EE. Hind wings normal. Stridulatory palar pegs 

 well developed, curved in single row. 



Arctocorixa Wallen. 



* Doctor Abbott has now given up this work, and the writer has the task of completing 

 Doctor Abbott's work. He is permitting the keys to stand for the present as first written. 



