THE CANADIAN ENTOMOLOGIST. 209 



number, but as it gives quite a preponderance of left-tegmen-uppermost, I 

 would not be surprised if we have here an isolated colony where " left- 

 wingedness " in the male is common — a survival of a more generalized 

 state, perhaps. I hope to get more material from there. Meanwhile, I 

 would like to ask those all over the country who have opportunity, to 

 e.xamine the male crickets with this simple point in mind. I would be 

 extremely grateful for any such material or information regarding it. It 

 has a bearing on several very important questions. 



A FOSSIL WATER-BUCx. 



BY T. D. A. COCKERELL, BOULDER, COLO. 



Among the fossil insects collected at Florissant, Colo., by Judge J. 

 Henderson and Dr. F. Ramaley, of the University of Colorado, is a 

 species of Corixidse, represented by numerous individuals. It occurred, 

 as Judge Henderson informs me, in the first railroad cutting east of 

 Florissant, a little above the middle of the section there exposed. 

 The shale containing the specimens is very much lighter than 

 that in which the other Florissant fossil insects seen by me are imbedded, 

 and it is believed to belong near the top of the series. It may represent 

 a later period than that in which most of the numerous species described 

 by Scudder lived, and it is certain that the insects now described differ 

 from the three species of Corixidse described from Florissant. 



Corixa Florissa?itella, n. sp. 



Length, ^yj, mm.; breadth, 2^ mm ; corium and membrane 

 minutely reticulated, not at all striated ; face convex ; scutellum concealed 

 by pronotum, except posterior angle ; pronotum without visible markings; 

 corium with the margins of the posterior (apical) part rather broadly 

 pallid, and with a broad, more or less distinct transverse dark band just 

 above the beginning of the membrane; just before the dark band is a 

 suffused light band, and in front (basad) of this the corium is dark: 

 membrane black ; abdomen ending in a pair of large subtriangular plates, 

 not asymmetrical ; swimming (posterior) legs well developed, hairy as 

 usual, extending about V^ mm. beyond end of abdomen. Length of 

 tegmina, 4)^ mm.; breadth about i mm.; middle legs projecting about 

 4 mm. beyond body. Florissant. Following Kirkaldy's table (Entomolo- 

 gist, 1905, p. 234) this would seem to be a genuine Corixa, but it lacks 

 pale lines on the pronotum. In Scudder's table of the Florissant species, 

 it falls with C. Vandiizeei, Scudd.^ but that differs entirely in the markings, 

 and probably belongs to the genus Callicorixa. 



June, 1906 



