NEUROPTBRA— TWCBOPTERA— HYDROPSYCHID^. 187 



in the middle of the wing, the costal margin falling obliquely to the tip 

 over a considerable area, and the apical margin equally oblique below the 

 apex ; the contrast in the length of the first and second apical cells is very 

 marked ; the cross-vein uniting the sector and cubitus falls at the origin of 

 the second apical cell, and the median and discoidal cells originate side by 

 side ; none of the cross-veins are sliown in the plate The wing is clear, 

 excepting for a slight infuscation along the costal edge and the infuscation 

 of the veins. 



Length of body, 10°"°; of front wings, 10°"" ; breadth of same, 3.35°"° ; 

 length of fore femora, 1.7""; tibiae, 1.7""°. 



Florissant. One specimen, No. 14210. 



5. LEPTOBROCHUS gen. nov. {XeTrro?, j3p6xo?). 



This genus, which includes only one species, is remarkable for lacking 

 not only the fifth, but the second, apical cell. In other respects it does not 

 differ from Derobrochus, except in having, as in Litobrochus, an extremely 

 long median cell, due, however, not to the extension of the cell toward the 

 margin, but to its basal extension by the earlier origin of the middle branch 

 of the upper cubital vein. 



Leptobrochus luteus. 

 PI. 15, Figs. 1, 3. 



This abundant species is rarely well preserved. It has a slender body, 

 long and narrow wings, very slender legs, and antennae longer, so far as 

 known, than any other of our fossil species, being much more than twice 

 the length of the body (including the closed wings) ; the joints are about 

 four times longer than broad, very slender, and the incisures marked with 

 fuscous ; the first joint is stout and obovate. The front wings are very 

 long and slender, the apex produced, subacuminate and scarcely above the 

 middle ; the first apical cell is tolerably small, and the discoidal cell appar- 

 ently open ; the median cell, however, is closed, and the cell itself exceed- 

 ingly long, the closure being a little before the origin of the third apical 

 cell, which is not quite so long as tlie breadth of the wing and shorter than 

 the fourth apical cell ; these features of the neuration do not appear in the 

 figures on the plate. 



