HUNGERFORD: AQUATIC HEMIPTERA. 215 



tends from thorax to about the level of the third abdominal segment. 

 Strigil ovate, about 0.3 mm. long, by 0.2 mm. wide, transversely placed, 

 with 6 to 7 striae. Legs and entire under surface yellowish white. 



"Male palse very strongly compressed, plate like, the lower edge 

 straight, the upper edge parabolic in outline; the surface covered with 

 fine depressed spines. Toward the lower edge, next the tibial joint, are 

 found the "pegs" in two rows, 5-6 in the upper row, 9-10 in the lower. 

 These two rows seem rather sharply differentiated from the rest of the 

 spines covering the face of the pala, yet it would seem to be not im- 

 possible that the whole surface may function in stridulation. The lower 

 edge of the pala is fringed, but there is no terminal spine. Tibia globular, 

 about one-fourth the length of the pala. Femur oblong, as long as the 

 pala, its width about one-half its length. Stridular area large, consist- 

 ing of numerous rows of minute spines. Female palje short cultrate, 

 triangular in section, the length a little less than three times the greatest 

 height. Tibia rounded oblong, about as wide as the pala, its length a 

 little more than twice its width. Femur trapezoidal in shape with a dis- 

 tinct area of strong spines analogous to the stridular area in males. 



"Second leg: Spines about equal to tibia in length, the latter one-half 

 the femur. Tarsus slightly shorter than tibia. Third legs: Femur and 

 tibia subequal and about four-fifths the tarsus. Metaxyphus short, acute. 



"Length, 6 mm. ; width across pronotum, 1 Vo mm. 



"Described from three males and thi'ee females from Fort Collins, 

 Colo., collected in May and June by Prof. C. P. Gillette, to whom the 

 author is indebted for the specimens. Superficially the species resembles 

 calva Say, vdth which it possibly has been confused. It is considerably 

 larger than Say's species and structurally very different from any other 

 Corixid with which the writer is familiar." 



Genus ARCTOCORIXA Wallen 1894. 



The scutellum is covered except sometimes at posterior angles by 

 pronotum. Tegmina without short black hairs. Asymmetry on right 

 side. Palor stridulator never with bristles although the pegs may be 

 elongate. Strigil present. 



B. Biology of Corixid^. 



General Notes. The water boatmen spend most of their time upon the 

 bottom of the pool, where they feed upon the flocculent deposits of ooze 

 containing diatoms, desmids, filamentous algae, oligochetes, etc. This 

 food they gather with their front legs. They fasten their yellow top- 

 shaped eggs to submerged brush or vegetation. One species places its 

 eggs upon crayfish. The adult males chirp by rubbing the front tarsi 

 against the beak or the femur of opposite leg. 



The writer submits herewith notes on but three species. He has reared 

 a considerable number, but intends to report upon them in an extended 

 monograph of the Corixidje now in preparation. The three species chosen 

 represent three genera and illustrate the diversity of habits in the group. 



Rnwphocorixa acuminata Uhl. 



Doctor Abbott has written two papers on the biology of this species, 

 one dealing with the manner of its oviposition and the other some notes on 

 the life history, together with a description of the instars. It is indeed a 

 remarkable form and Doctor Abbott described it as a new genus and new 

 species when it came to his hand. He has since decided that it is the 

 same as Arctocorixa acuminata Uhl., though the bug is much more 



