Vicinity of Mazon Creek, Illinois. 



313 



far away from the radius and sending obliquely toward the 

 apical border 6 partly simple, partly forked branches, the 

 first of which rises quite in the basal half of the wing. Medial 

 vein independent, not meeting with the sector and branched 

 in a singular manner : beginning from the base, we first find 2 



Fig. 17. 



Fig. 18. 



Fig. 17. Gerarus latus. xlS. 



Fig. 18. G. collaris. xl-4. 



short branches directed backward and not reaching the mar- 

 gin; the stem then bends obliquely to the posterior margin, 

 emitting obliquely forward 4 branches which retain the primi- 

 tive direction of the media. Cubitus comparatively little 

 expanded, scarcely reaching the apical half of the wing and 

 giving rise to but 3 short branches which are directed back- 

 ward. The long and pointed anal area may have been pro- 

 vided with about 5 veins. Traces of the long neck are to be 

 seen. 



Holotype in Peabody Museum, Yale University, Cat. No. 33. 



Am. Jour. Sci.— Fourth Series, Vol. XXXI, No. 184.— April, 1911. 

 92 



