196C. SVXOPSIS OF NEOTROPICAL LIMXOBIN^TH—ALEXA XOTR. 525 



I will not attempt to decide witliout liavmg European material for 

 comparison. The data for the Mexican specimens are as follows: 



C"6rdoba, Mexico, December IS, 1907, male and female; February 

 n, 1908, male and female; Febnuuy 16, 1908, two females; March 

 1-', 1908, three females: March 16, 1908, male. Orizaba, Mexico, 

 March 13, 1908, male and female (Fred. Knab, coll.). 



KEY TO THE GENER.\ OP THE LIMNOPHILINI. 



(Based largely on Needham's key, 1907.) 



1. Ocelli pre.wnt 2. 



Ocelli ab.sent 3. 



2. Cell M, present; basal deflection of Cu, near the outer margin of cell first M_. 



(i. e., fusion of Cu, and M, very slight) Trichocera Meigen. 



Cell M, absent; basal deflection of Cu, at, or near, the fork of M (i. e., fusion of 

 Cu, and M extensive) Ischnothrix Bigot. 



3. Radial cross vein absent Phijllolabis Osten Sacken. 



Radial cross vein present 4. 



4. Cross vein m absent; fusion of Mj and Cu, long and ending in a symmetrical 



fork Polymera Wiedemann. 



< ross vein m present; fusion of M^ and Cu, usually short; fork not symmetrical. .5. 

 .5. Wings pubescent; two branches of M Ulomorpha Osten Sacken. 



Wings glabrous (usually); if pubescent, three branches of M at the wing margin. .6. 

 «>. A supernumerary cross vein in cell C Epiphragmo Osten Sacken. 



Xo supernumerary cross vein in cell C 7. 



7. -Vntenua of male with long pectinations; .usually with more than 16 segments. 



Cledonia Philippi. 

 .Vntenna; of male of various shapes, but never pectinate; IC-segmented 8. 



8. So very long, approximating R, at wing-margin Lecteria Osten Sacken. 



Sc shorter, alway.* distant from R, at the tip. . .'. Limnophila Macquart. 



Genus ISCHNOTHRIX Bigot. 



IschmOirir Bigot, Miss. Sci. Cape Horn, Zool., pt. G, 1888, pp. 7, S, pi. 2. 

 Mak. — Related to the genus Trichocera. Antennae hair-like, 

 two or tliree times as long as the body, with 13 or 14 (?) segments, 

 segment 1 short, stout, second scarcely visible, the remainder 

 elongated, cylindrical, attenuated apically; rostrum almost as long 

 as the head, liorizontal, abriiptly truncated at the tip; palpi 5 

 segmented, the fifth not much longer than the others, indistinctly 

 furrowed; three oceUi; feet very long, smooth, not swollen: wings 

 margined with short hairs, twice as long as the abdomen: first and 

 second longitudinal (Rondani) veins separate at their tips: three 

 veins emerge from the pentagonal discal cell, widely separated 

 basally, not forked; from the first basal cell, two veins, the outer 

 forked; hypopygium small, clasping: abdomen scantily clotheci 

 \vith fine hairs on both sides. (Bigot). 



ISCHNOTHRIX iETHEREA i Bigot . 



Male. — Eight mm. Antennae testaceous, broadly infuscated at 

 the tip; palpi black; rostrum brown, tip tinged with black; head 



