NBUROPTERA— TRICHOPTERA— HYDROPSYCHID^. 1 83 



Base of first apical cell considerably, or very much, farther from the root of the wing than the base of 

 any other apical fork. 

 Third and fourth apical colls about equally distant from base. 



Second apical cell less than oue-third as long again as the third 3. D. wternm. 



Second apical coll half as long again as the third 5. D. marcidiis. 



Fourth apical cell reaching much nearer the base than the third 7. D. craterw. 



1. Derobrochus abstractus. 



A single specimen, preserver! on a side view, so as to show the upper 

 half of the under surface of the right front wing, and in addition the upper 

 surface of the whole of tlie left front wing, overlying the hind wing and 

 confusing the neuration. Little besides the wings can be seen, but the 

 stout cylindrical basal joint of the antennae appears, followed by a few sim- 

 ilar but much slenderer joints. The front wing is slender, subacuminate 

 at tip, the costal margin falling toward the tip at about the same angle as 

 the apical margin retreats from it, the apex itself rounded off, and rather 

 above the middle line of the wing. The first apical cell is remarkably long, 

 the fork originating at the end of the middle third of the wing, and of the 

 same length as the thii-d apical cell ; the second apical cell is only a little 

 longer. The wing is apparently clear, with the veins narrowly marked 

 with fuscous and faintly irrorate with fuscous at their tips. 



Length of body, 9™™; of front wing, ll"""; width of same, S.S"". 



Florissant. One specimen. No. 9377. 



2. Derobrochus c^nulentus. 



This species is represented again by a single specimen, showing a dor- 

 sal view of a vague body with outstretched front wings, one of which is 

 nearly complete and tolerably well preserved, showing a portion at least of 

 the neuration with clearness. The wing is not so acuminate as in the pre- 

 ceding species and the apex is in the middle of the wing. The first apical 

 cell thoug-h long- is shorter than in D. abstractus, but extends farther toward 

 the base than either the third or fourth cell, these last being much shorter 

 than in the preceding species. The discoidal cell is apparently fuU}^ as long 

 as the median cellule, but its limits are not clearly marked ; the latter is as 

 long as the fourth fork and veiy slender. The wing appears to be clear with 

 infuscated veins, and the whole costal margin broadly but faintly infuscated. 



Length of wing, 8.5'"'°; breadth of same, 2.6"""; length of median cel- 

 lule, 2°"". 



Florissant. One specimen. No. 14444. 



