134 DIPTERA 
22. GENUS ATRICHOPLEURA, BEZZI 
Atrichopleura, Bezzi, Nova Acta Akad. Naturf. Halle, Vol. 9r, p. 302, 357 (1910). 
Characters. — Slender or robust blackish species, two to four millimeters in length. Head 
globular, the antennz inserted near the middle of the head, eyes of both sexes widely separated, bare, 
the facets not enlarged, marginal incision at the antennz deep, ocellar triangle not elevated, ocellar 
bristles long and divergent, several diverging fronto-orbitals, face quadrate, sometimes bearing hairs ; 
antennze rather shorter than the head, basal joints subequal, more or less globular, not setose, the third 
joint narrowly conical, with a thickened terminal style shorter than the third joint and not geniculate at 
the short basal section; proboscis about as long as the head, projecting obliquely forward, labrum 
shorter than the labium, the labellar flaps broad, palpi long, cylindrical, up-turned, with a few long 
hairs. Thorax small, bristles weak or strong, one humeral and one posthumeral, the anterior 
dorsocentrals weak and numerous, several scutellars, the acrostichals weak and biseriate ; pleure 
entirely bare, Abdomen typically slender, twice as long as the thorax, with weak hairs; pygidium 
typically rather small, closed, no projecting valves, penis filiform; abdomen of the female tapering. 
Legs simple, of the female without bristles, of the male the anterior tibize sometimes densely pubescent. 
Wings long and narrow or short and broad, the costa encompassing the entire margin, auxiliary veiri 
straight, distinct, not meeting the costa, third vein simple, anal vein obsolescent, no alula, typically the 
anal angle broadly rounded and the anal crossvein abruptly and greatly reflexed, parallel with the axis 
of the wing. 
Type species : A. Scineusei (Pl. 6, Fig. 60), by Bezzi's designation. The genus Arichopleura 
is a composite which ultimately will probably be subdivided. The species mitida has the habitus of 
Hilara, crassa resembles Schistostoma, while Schmeusei and hirtipes are slender insects with long narrow 
wings and more or less hairy face. The genus appears to be restricted to South America. 
Geographical distribution. 
1. A. argyriventris, Becker, Mission Arc Méridien Amér. Sud, Vol. 10, p. 171. Ecuador. 
(1919). 
. crassa, Bezzi, Nova Acta Acad. Naturf. Halle, Vol. gr, p. 359 (1910). Chile. 
. hirtipes, Bezzi, ibidem, Vol. 91, p. 361 (1910). Peru. 
. nitida, Bezzi, ibidem, Vol. 91, p. 358. Peru. 
. Schneusei, Bezzi, ibidem, Vol. 91, p. 362 (1910). — Pl. 6, Fig. 60. Peru. 
. tephrodes, Philippi, Verh. Zool.-bot. Ges. Wien, Vol. 15, p. 760 [1865] Chile. 
(Rhamphomyia); Bezzi, Nova Acta Akad. Naturf. Halle, Vol. 9r, 
p- 323 [1910] ( ? Rhamfhomyia). 
OV Ub wo 
5». 
23. GENUS OPEATOCERATA, NOV. GEN. 
Characters. — Small, polished yellow species suggestive of Lepfopeza, measuring about three 
millimeters in length. Antenne inserted below the middle of the head, joints small, slightly pubescent, 
the third joint short-ovate, tipped with a lengthened two-pieced arista three times the length of the 
third joint, of which the basal part is two-thirds the length of the third antennal joint and appears like 
a prong-like extension of that joint; proboscis inflexed, slender, slightly longer than the head-height. 
Thorax strongly convex, bristles very delicate and yellow, no pubescence, dorsocentrals uniseriate, no 
acrostichals, humeral, posthumeral, notopleural or presutural sete, two supra-alars, two parallel 
scutellars; propleurz bare, a row of long delicate metapleural hairs, prothoracic spiracle concolorous, 
