208 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



tion, last joint button-shaped, with a short cylindrical prolongation, 

 which may be taken for a 16th joint. Scutelluin projecting. Abdomen 

 of the usual length, ending in the male in a large double-branched 

 forceps. The fourth tarsal joint has a small projection on the under 

 side at the basis (probably a sexual character). Wings narrower than 

 in P. fitchii, and anal angle less projecting,- venation like 1. c, p. 317, 

 f. 7, but the cross-vein in the fifth posterior cell is wanting, and there 

 is no stump of a vein at the origin of the second vein. 



P. vipio has the same venation as Macrochile Loew (Linn., Entom., v, 

 tab. ii, f. 25), but differs in having 15- and not 19-jointed antennae. It is 

 also closely allied to Tanyderus Philippi (Verh. zool.-bot. Ges., 1865, p 

 780). The venation is very like that represented 1. c, tab. xxix, f. 57c. 

 only the small cross-vein in the first posterior cell is wanting; the 

 first vein and the branches of the second are more straight, the anal 

 angle more rounded. The neck-like prolongation of the thorax is not 

 quite as long as represented by Philippi. The antennae of Tanyderus 

 are said to be at least 25-jointed. 



Dr. Philippi's statement that the abdomen of Tanyderus ends in two 

 filaments does not warrant his conclusion that the specimen is a male. 



Protoplasta vvpio has a forceps, each of the two halves of which resem- 

 bles the thumb and forefinger of a hand when divaricate; that is, each 

 half has two branches, with a deep and broad sinus between them. This 

 forceps, which I observed and sketched from the fresh specimen, has 

 retained its shape after drying. It seems only probable that both P. 

 fitclii and Tanyderus have a forceps constructed more or less on the 

 same plan, and that the specimens hitherto described were females. 



The sexual characters of P. fitclii not being as yet known, and P. 

 vipio being known in the male sex only, I prefer to leave them provis- 

 ionally in the same genus, although in the future a generic separation 

 may become necessary. 



Protoplast A vipio n. sp.— Male. — Body brownish-gray ; palpi and 

 antennae black, a brown spot above each eye and a brownish line in the 

 middle of the front; thorax with three brown stripes, the intermediate 

 double; dorsal segments of the abdomen brownish in the middle, gray- 

 ish posteriorly and on the sides, sparsely punctured with brownish-black; 

 two larger dots of the same color in the middle of each segment. Legs 

 brown, except the femora, which are reddish-yellow, brown at tip ; wings 

 subhyaline, with blackish spots, dots, and cross-bands, a double spot 

 near the root, another spot at the base of the praefurca, an irregular 

 cross-band beginning at the end of the auxiliary vein and ending at the 

 hind margin in the spurious cell ; a second interrupted cross-band begins 

 in the region of the stigma and ends on the hind margin in the two last 

 posterior cells; numerous blackish dots in the cells and at the end of 

 the longitudinal veins. Length of the body about 10 mm . 



#a&._California (San Mateo Creek, near San Francisco, April 9, 

 1876). A single male. tw^si. 



