3o2 ; DIPTERA 
Characters. — Minute species, scarcely over one millimeter in length. Head large, globular, 
the eyes densely short-pubescent, enlarged below, obliterating the face, the lower facets large in both 
sexes, hind margin of the eye curving forward below, front narrow, its sides parallel, ocellar bristles 
small, two small vertical bristles present, cheeks narrow. ^ Antennz short, the first joint vestigial, the 
second joint swollen, with setze beneath, the third joint very short and round, with a dorsal geniculate 
arista, or rather, there is a short dorsal process arising from the third joint which bears the single-jointed 
arista. Proboscis short, vertical, palpi slender, with a strong apical bristle. Thorax broadly round, 
the dorsum moderately convex, shining or slightly pollinose in front, no discal bristles, but the hairs 
seriately arranged to form two acrostichal and one dorsocentral rows, one humeral bristle present, two 
notopleurals, no prescutellar, two scutellars; pleurze bare and shining, the metapleurz velvety. Abdomen 
without pits, comprising eight segments; the pygidium large and forcipate. Legs short, the front pair 
robust, in the males of come species the middle legs are ornamented and the hind legs are ciliate with 
long bristles, middle femora with a preapical bristle, no tibial apical spines. Wings narrow, first and 
second veins very short, third and fourth veins diverging, anal cell entirely wanting, costal bristle small. 
Nomenclature. — Concluding his description of Tachydromia celeripes, Meigen stated that he 
had received « mehrere Exemplare von Herrn von Winthem, unter dem Namen Agafachys flavipes.» This - 
induced Coquillett to adopt the name Agafachys for this genus. The catalogues have considered 
Agatachys as a manuscript name and as a synonym of Stilpon. While it is unfortunate that Loew 
overlooked Meigen's celeripes and Winthem's generic name when he formed the genus S/ilfon, yet his. 
name is so well known that is seems an unnecessary perversion of the rules to make Meigen the 
unwitting sponsor of Agafachys in order to have it established. 
The genus Tetrameurella of Dahl represents a curious form with reduced venation. Dahl now 
believes that his specimens lacking the second vein are dimorphic individuals of graminum. The 
American species, &l«urifica, here described, also lacks the second vein, but is certainly specifically 
different from any of the other known species of Stifos. The short V-shaped front suggests Drafetis, 
but the antennze are two-jointed and bear a dorsal arista, as in Stilpon. ! 
Type species of Stilpon, S. graminum, Fallen (Pl. 4, Fig. 37), by Coquillett's designation 
in 1903. / 
SYNOPSIS OF THE AMERICAN SPECIES OF STILPON. 
r. Pleurz opaque pollinose except a circular spot filling the sterno- 
pleura; second vein wanting; legs yellow, the hind femora brown 
onthespicalthid,.- . . .. 4. . s. - 3 83.4 22- CNECPLBUBITIDA, DOV 8D C. 
Pleurz largely polished ; second vein complete, ending in the costa 
about midway between thefirst and third veins . . . . . . . . . ... ;, * «. 4 
(1) Stilpon pleuritica, nov. sp. — Female. Length : mm, Black, the abdomen testaceous, legs yellow, the outer 
third of the hind femora brown, mesonotum lightly pollinose, pleurze brown-pollinose except a circular spot covering the 
sternopleurze; second vein wanting. Head large, front relatively short, V-shaped, narrowed below, lightly pollinose like 
the vertex ; antennae uniformly testaceous ; proboscis brown, palpi yellow with a small apical black bristle. Humeral bristle 
strong, notal hairs very short and sparse; lower part of the metapleurze shining ; one strong preapical bristle on the middle 
femora; hind metatarsi and last tarsal joint not darkened. Halteres entirely pale yellow. Wings with a slight infumation, 
the third and fifth veins more strongly bordered, veins brown becoming pale at their base, only a minute basal spur of the 
second vein remaining, proximal section of the fifth veinslightly shorter than the distal section. 
A single specimen from Mrs. Annie T, Slosson, collected in the White Mountains, New Hampshire.  Thisisa 
T /iraneurella form, — The V-shaped front and pollinose pleura are different from the characters of the other species of Stilpon. 
