752 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



liarities of this have been poiuted out in tlie description of the genus ; 

 but a few minor points, probably of specific value, may be added. The 

 second longitudinal vein originates far back toward (perhaps before) the 

 middle of the wing, and half-way to the tip forks abruptly, the anterior 

 branch immediately arching over and running to a point just above the 

 extreme tip of the wing; the space between this portion of its course and 

 the first vein is infuscated, forming a stigma ; the posterior branch forks 

 half-way toward the tip, the upper branchlet being in almost direct con- 

 tinuity with the main branch, while the lower diverges suddenly from 

 it and unites with the cross-vein from the third longitudinal vein, after 

 which it runs parallel to the other branchlet ; the third longitudinal 

 vein springs from the posterior branch of the second directly after its 

 origin. The first and second posterior cells are of the same length as 

 the lower two submarginal cells, and the discal cell is of a similar length. 

 The lower part of the wing is confused from folding, but there is a cross- 

 vein uniting the fourth and fifth longitudinal veins next the inner ex- 

 tremity of the discal cell ; the discal cell extends further by its own width 

 toward the base of the wing than the secondary discal cell, and there is 

 a slight appearance on the stone, as if the middle of the cross-vein 

 forming the inner limit of the discal cell were united by a cross-vein to 

 the second longitudinal vein shortly before it branches, thus forming a 

 prediscal cell of irregular shape and about as long as broad. Length 

 of fragment 5.5™™; width of middle of wing 2™™. Fossil Canon. 



Tipida decrei)ita. — A single specimen, poorly preserved, is to be re- 

 ferred to the genus Tipula (s. str,). The head is small, the antennal 

 joints very slender, obovate, between two^ and three times as long as 

 broad, the thorax well arched, and the abdomen indicating a female ; 

 the legs are wanting; both the wings are present, but poorly preserved, 

 and one of them imperfect ; even the perfect one is badly folded longi- 

 tudinally, but the costal border is nearly uninjured, and indicates the 

 generic affinities, from the peculiar nature of the venation toward the 

 apex; instead of forming toward the termination of the first longitudi- 

 nal vein-a large stigma-like cell, the second longitudinal vein appears to 

 form, with a slight vein springing from below, a long and exceedingly 

 slender cell, above and outside of which the wing is slightly clouded. 

 Length of body without head 6"™ ; diameter of head 0.6™™ ; length of 

 wings 8.5"^™. 



Tipula tecta. — A single specimen, preserved on a dorsal aspect, is of 

 a larger size than the other TlpuUdw from this locality; its precise 

 relationship cannot be determined until other specimens are discov- 

 ered, as it has no head nor legs, except a very slender fragment of a 

 tibia ; and the wings, being longitudinally folded and partially concealed 

 by the body, along which they lie, show only that the neuration is not 

 discordant with that of the crane-flies, with which its other features 

 agree. The specimen is a female, with a slight, not greatly arched, 

 thorax, and full and plump, though still slender, abdomen, nearly as 



