576 TERTIARY INSECTS OF NORTH AMERICA. 



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 continuity 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 longitud- 

 inal 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 extremity of 

 the discal cell ; the discal cell extends farther by its own width toward the 

 base of the wing than the secondary discal cell, and there is a slight appear- 

 ance 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 mm ; width of middle of wing, 2 mm . 



Fossil Canon, White River, Utah. (W. Denton.) 



TIPULA Linnd 



TlPULA DECREPITA. 



PI. 5, Figs. 56, 57. 

 Tipula decrepita Scuild., Bull. U. S. Geol. Geogr. Surv. Terr., Ill, 752 (1877). 



A single specimen, poorly preserved, is to be referred to the genus 

 Tipula (s. str.). The head is small, the antennal joints very slender, obo- 

 vate, between two and three times as long as broad, the thorax well arched, 

 ami the abdomen indicating a female ; the legs are lacking ; both the wings 

 are present, but poorly preserved, and one of them imperfect; even the 

 perfect one is badly folded longitudinally, 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 longitudinal vein a large stigma-like cell, the second longitudinal 

 vein appears to form, with a slight vein springing from below, a long and 



