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Genus Mochlonyx. 
legs of Say’s or Loew’s species, merely “ legs with numerous brown 
dots ”; “ the first tarsal joint fuscous at the apex, apices of the 
femora and bases and apices of the tibiae banded black, &c.” 
And as the species of Corethrti seem very restricted in habitat, 
I think it is best to describe this small gnat as a new species, 
until Say’s type or specimens from Pennsylvania can be obtained. 
Genus 22.— MOCHLONYX. Loew (1844). 
Corethra Ruthe. 
(Eut. Zeit. Stett. y. 121, Loew; Ins. Brit. Dipt. iii. 252, Walker.) 
Proboscis short in the male and female, a little longer than 
the head. Palpi twice as long as the proboscis, four-jointed ; 
antennae fifteen-jointed, the last two joints longest and verti- 
cillate, joints increasing in size from the base to the apex. 
Wings with the cross-veins nearer the base of the wing than in 
Corethra; fork-cells long, the stems short, much less than half 
the length of the cells, veins otherwise much as in Corethra. 
The legs have the first tarsal joints always longer than the metatarsi , 
ungues moderately large, serrated. 
There have been two species of this genus described, both 
from Europe. The two species are recorded in England, 
M. velutinus, Ruthe, and M. effoetus , Haliday. I believe these two 
to be the same. 
Although the adult resembles chiefly Corethra , the larva 
most nearly approaches the Culex type, being provided with a 
respiratory siphon (vide p. 49, Yol. I.). 
1. Mochlonyx velutinus. Ruthe, 
M. effoetus. Walker. (Haliday MS.) 
(Isis. 1205 (1831), Ruthe; Ius. Brit. Dipt. iii. p. 252 (effoetus), Walker.) 
(PI. 132, PI. XXXIII.) 
Head, antennae and palpi brown, antennal plumes of the 
yellowish-brown to flaxen. 
Thorax dark brown, with golden-yellow hairs and two closely 
applied longitudinal median stripes ; scutellum and metathorax 
brown. 
