184 TERTIARY INSECTS OF NORTH AMERICA. 



3. DEROBROCHUS ^ETERNUS. 



This species is again represented by a single specimen but in a better 

 state of preservation than the preceding forms. It presents a side view 

 with the upper front wing well preserved, and the lower, though visible by 

 drooping, obscure. The legs are tolerably well preserved but confused ; 

 they are sparsely clothed with hairs and the tibial spurs can not properly be 

 distinguished. The front wing is slender, broadest only a little way beyond 

 the middle, the apex well rounded, and the apical margin very oblique but 

 full. The discoidal and median cells are about equally long and slender 

 and nearly as long as the second apical cell, which is fully one-third the 

 length of the entire wing. The third and fourth apical cells are of about 

 equal length and nearl y twice as long as the first. The anastomosis is very 

 simple, the cross-veins closing the discoidal cell and uniting the sector and 

 cubitus falling together just beyond the origin of the second apical fork. 

 The wing as preserved is clear in the apical fourth but elsewhere irrorate 

 with fuscous, the veins everywhere infuscated. 



Length of front wing, 9.75 mm ; breadth, 4.1 mm . 



Florissant. One specimen, No. 5308. 



4. DEROBROCHUS COMMORATUS. 



A species closely allied to the last described, and mainly distinguisha- 

 ble from it by its shorter and much slenderer wings. A number of speci- 

 mens appear to belong here, but none of them are very well preserved. 

 The body is slender, the legs long and slender, but with rather stout femora, 

 the front legs short and slight. There is a single pair of spurs on the front 

 legs, and two pairs on the hind legs. The front wings are pretty uniformly 

 fuliginous with fuscescent veins ; it is very slender, broadest close to the 

 apex, the tip rounded and placed considerably above the middle, the apical 

 margin much less oblique than in D. seternus. The neuration is identical 

 with that species. 



Length of body, 8.5 mm ; of front wing, 9 mm ; breadth of same, 2.75 mm ; 

 length of fore femora, 1.6 mm ; of fore tibia, 1.1 mm ; of middle femora, 3.25 mm ; 

 of hind tibia, 2.6 mm . 



Florissant. Ten specimens, Nos. 2661, 3237, 3343, 3350, 6848, 13539, 

 13542 and 14170, 14029, 14171, 14312. 



