220 



apices with truncated knobs. The abdomen is furnished upon the 

 middle of the dorsum of the second and sixth segments with a rough- 

 ened plate clothed with short coarse spines, and the intervening seg- 

 ments each have 2 such plates, one before, and the other behind, the 

 middle. Ventral segments 3-7 each with a pair of widely separated 

 papilliform tubercles in a transverse line at middle. Apical segment 

 elongate, without spines. 



This species is aquatic in the larval stage, but pupates in moist 

 earth along the banks of the streams in which the larvae occur. The 

 larvae feed upon the worm Tubifex rivulorum. 



Rhaphidolabis Osten Sacken 



I have but one larva that I regard as belonging to this genus. It 

 very closely resembles that of Dicranota, differing in being slightly 

 more slender ; in having the pseudopods armed with a more regularly 

 curved semicircle of apical spinules, the spiracles much smaller and 

 less elevated, the apical processes longer; and in the apparent absence 

 of the ventral blood-gills. 



This specimen was taken by Dr. S. A. Forbes among vegetable 

 refuse in Blacktail Deer Creek, Yellowstone National Park, August 

 28, 1890. 



The larva of R. tenuipes has been figured by Needham*. 



The species are aquatic in the larval stage, occurring in streams. 



Subfamily LIMNOPHILINAE 



I have before me representatives of but one genus of this sub- 

 family, and have found descriptions of but two others of the ten 

 genera which it contains. 



SUBFAMILY CHARACTERS 



Larva. — Head well chitinized, much as in Tipula, the principal 

 differences being the much longer maxillary palpi, which exceed the 

 antennae in length, and the less robust mandibles. The labium also 

 shows a departure from the tipulid type and is produced into a rather 

 acute central point anteriorly, but the genera in which the structure 

 of this plate is known to me differ materially, and a generalization is 

 not justifiable, more particularly as both forms are found in other 

 subfamilies. Apical abdominal segment with 4 or 5 protuberances on 



'Twenty-third Rep. N. Y. State Ent., p. 201. (1908) 



