344 TERTIAEY INSECTS OF NORTH AMERICA. 



Notonectidfe, subrotund, but eiubi-acing the thorax posteriorly as in Corixa.; 

 it has a median sulcation. The thorax is remarkably large, broader than 

 the head, only about twice as broad as long, well rounded, posteriorly 

 truncate, separating off a large triangular scutellum (again like Notonecta) 

 whose posterior sides are convex and the apex rounded ; it is only a little 

 shorter tlian the thorax and about half as broad as it. The hemelytra are 

 broad and well rounded, the clavus very broad, the membrane indistin- 

 guishable from the corium, the apex well rounded, the tips of the opposite 

 pairs overlapping as in Sigara ; the veins are numerous and divergent like 

 the rays of a fan. The legs are long and slender, the middle pair nearly as 

 long as the body, the tarsi biarticulate, thejoints subequal. 

 A single species is known. 



Prosigara flabellum. 

 PL 22, Fig. 12. 



A sinsrle specimen, showing a dorsal view. The whole body is dark 

 gray and the hemelytra delicately mottled, through which the dusky veins, 

 growing darker apically, make their way, and, radiating in the broader apical 

 part of the corium, from which the membrane is indistinguishable, form the 

 most conspicuous feature of the markings ; none of the last, however, appear 

 in the clavus. The tarsus of the middle legs is not shown in the figure. 



Length of body, 6°""; breadth, 1.85"""; length of tegmina, 3.5°""; 

 breadth, 1.4"" ; length of middle (?) leg beyond side of body, 5°"". 



Florissant. One specimen, No. 1098. 



CORIXA Geoffroy. 



As stated above, two European species of this widely distributed genus 

 are known from the European Tertiaries, to which we are able to add two 

 others from Florissant with well defined characteristic markings. 



Taile of the species of Corixa. 



Tegmina more than four times longer than broad ...1. C. vanduzeei 



Tegmina less than four times louger than broad ...2. C. immersa. 



1. CORIXA VANDUZEEI. 

 PI. 22, Fig. 17. 



A very pretty species of about tlie size and form of C alternata Say, 

 but more nearly allied to C. interrupta Say, not only in markings but also 



