9o DIPTERA 
Coquillett, Proc. Ent. Soc. Wash. Vol. 5, p. 253, 260 (1903); Melander, Williston Man. N. 
Amer. Dipt. p. 225 (1908); Bezzi, Nova Acta Akad. Naturf. Halle, Vol. 9z, p. 302 (1909); 
Kertész, Cat. Dipt. Vol. 6, p. ror (1909); Becker, Wien, Ent. Zeit. Vol. 28, p. 25-28 (1909); 
Coquillett, Proc. U. S. Nat Mus. Vol. 37, p. 570 (1910); Lundbeck, Dipt. Dan. Vol. 3, p. 189 
(1910); Wahlgren, Ent. Tidskr. Vol. 3r, p. 43, 77 (1910). 
Holoclera, Melander, not Schiner, Trans. Amer. Ent. Soc. Vol. 28, p 333 (1902). 
Schistostoma, Becker, Mitteil. Zool. Mus. Berl. Vol. 2, P- 46 (1902); Wien. Ent. Zeit Vol 28, p.27 
(1909); Kertész, Cat. Dipt. Vol. 6, p. 101 (1909). 
Characters. — Small usually opaque black hunchbacked species, the males with a twisted 
epipygium and large contiguous eyes. Head rather globular, the occiput flattened, eyes bare. of the 
female widely separated, of the male contiguous along the front, the facets of the upper two-thirds larger 
than below; antennz inserted rather below the middle of the head, three-jointed, the middle joint 
typically with strong setze above and below, the third joint compressed conical or more or less abruptly 
attenuated beyond the base, with a lengthened terminal arista which varies from one-half to three times 
as long as the third joint; proboscis usually retracted within the oral cavity, sometimes more or less 
protruding when the fleshy labium can be seen surrounding the chitinized piercing parts, palpi minute, 
cylindrical; bristles of the occiput not strong. Thorax greatly arched, robust, about as long as the 
abdomen, more or less bristly, with two or four rows of acrostichals, a row of dorsocentrals, some post- 
humerals and supraalars, as well as the usual humeral, notopleural, postalar and scutellar bristles, the 
last mentioned varying from four to eight in number; pleurz bare. Abdomen stout, cylindrical, clothed 
with long thin hairs in the male, epipygium twisted to the right, distorted, often very large. sometimes 
the last ventral segments of the male are spinose; no distinct ovipositor, but the last segments of the 
female abdomen compressed or tubular and shining. Legs short, often the femora and tibiz pectinate 
with bristles, and in the male, variously furnished with bristles which are lacking in the female. Fringe 
of the calypteres prominent. Wings large, anal angle full, costa encompassing the entire wing, stigma 
usually distinct, auxiliary vein distinct from the first and terminating in the costa, basal cells minute, 
discal cell large, complete. third vein simple, anal crossvein recurved, forming a jog in the under side — — 
of the anal cell, anal vein completely wanting. no alula but the alular cilia long. 
Type species : M. velutinus, Meigen (Pl. 7, Fig. 68), by Rondani's designation, 1856. 
Westwood indicated Trichina clavipes as the type, but Macquart did not have this species when he 
erected the genus Microphorus. The genus is restricted to the Northern Hemisphere. The species are 
not rare in shady woods where they are supposed to prey on smaller insects.  Beling has described the 
earlier stages of M. £usillus. The sort of sexual dimorphism exhibited by this genus is curious. Here 
and there on the body, such as on the middle trochanters and femora and on the under side of the 
abdomen, the males of some species have developed characteristic blunt spinous bristles. Again in other 
species the hind tibize and metatarsi of the males are swollen, but are normal in the females. 
SuBGENUS SCHISTOSTOMA, BECKER 
Characters. — Proboscis very short, not protruding, vertical, fleshy, palpi short, cylindrical, 
furnished with five or six setze; second joint of the antenne not setose, only some short setule present, 
third joint conical, longer than its arista; front of female with two fronto-orbitals. Only the posterior 
two or three dorso-centrals lengthened, one posthumeral, one notopleural, the setulze weak, two scutel- 
lars. Pygidium with several long filamentous appendages, ovipositor short and tubular. Alula some- 
what distinct, calypteres large, no basal bristle on the costa, 
