744 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



DIPTERA, 



Family Culicidj]], 



Cnlex proavitus. — A poorly preserved specimen, in wliicli only frag- 

 ments of the legs can be seen, and the wings are so crumpled and folded 

 as to prevent tracing the neuratiou. What can be seen resembles the 

 neuration of the Culicidw, and the veins and borders are heavily fringed 

 with long hairs. The body is slender and the insect minute ; the pro- 

 boscis is about as long as the head and thorax combined, and the last 

 joint of the equally long palpi. is cuneate, the base rounded. Length of 

 body 2.2™^; of proboscis 0.9""". Fossil Canon. 



Coretlira exita. — A specimen, viewed from above, with expanded wings, 

 and destitute of legs, j)alpi, and all but the basal joints of the antenna?. 

 The broad head, stout basal joint of antenna?, general form and size, 

 with such of the neuratiou of one wing as can be determined, indicate 

 the genus; seven of the abdominal segments are very clearly marked, 

 and the specimen appears to be a male. The body is slender; the head, 

 thorax, and abdomen of equal width; the wiugs slender and of about 

 equal length with the body. The fourth longitudinal vein runs in a 

 nearly straight line over the basal half of its course, but is gently arched 

 beyond; the fifth originates from the fourth in the middle of its straight 

 portion, runs nearly parallel with it so long as it continues straight, and 

 afterward diverges considerably: the first longitudinal vein appears to 

 run to the tip of the wing. Length of body 4.25™™; of wing 4.*25™™; 

 breadth of latter O.S""". Chagrin Valley. 



Family Chieonomid.e. 



CJiironomus dejjletus. — A single mutilated specimen of this insect 

 remains, and is doubtfully referred to CJiironomus. The thorax is mod- 

 erately robust, and the abdomen rather plump for a GJdrononius. The 

 antennae are broken, and only the costal border of one of the fore wings 

 can be seen; this shows that the second longitudinal vein terminates in 

 the middle of the apical, and the first longitudinal apparently in the 

 middle of the basal, half of the wing. The legs are moderately long, 

 slender, the tibiee finely spined, the spines arranged on the middle legs 

 in a somewhat verticillate manner, and terminating with two or three 

 long spurs; the femora are rather short, the tibioe considerably longer, 

 but not so long as the tarsi. Length of body 3™™; of wing 2.3™™; of 

 fore femora 0.68™™; of fore tibi?e 0.6 ™™; of fore tarsi 1'"™; of middle 

 tibise 1™™; of middle tarsi 1.25™™. Chagrin Valley. 



Chironomus patens. — A single specimen, very well preserved, repre- 

 sents a species which is provisionally referred to Chirononms. jSTearly 

 all the parts are present, and the neuration of one of the wings is nearly 

 perfect, showing the structure of Chironomid(v, but differing apparently 

 from any genus yet characterized. The antenna? are parted and bent, 

 but apparently perfect; they seem to be fifteen-jointed, the joints square. 



