FAM. EMPIDID/E 297 
9. Ch. lutescens, Bezzi, Ann. Mus. Hungar. Vol. 2, p. 358 (1904). New South Wales. 
10. Ch. nana, Coquillett, Proc. Ent. Soc. Wash. Vol. 5, p. 166 [1903] (Colo- Florida. 
boneura). 
11. Ch. speculifera, Walker, Ins. Brit. Vol. r, p. 138(1851); Bezzi, Bull.Soc.Ital. C. & S. Europe. 
Vol. 3o, p. 151 (1899); Becker, Zeitschr. Hym. Dipt. p. t19 (1907). 
I2. Ch. species, Bezzi, Ann. Mus. Hungar. Vol. 10, p. 491 (1912). Formosa. 
9. GENUS THINODROMI!A, MELANDER 
Thinodromia, Melander, Ent. News Philad. Vol. 17, p. 370 (1906); Williston's Man. N. Amer. 
Dipt. p. 222 (1908); Kertész, Cat. Dipt. Vol. 6, p. 169 (1909); Melander, Psyche, Vol. 17, 
P- 49 (1910); Coquillett, Proc. U. S. Nat. Mus. Vol. 37, p. 614 (1910). 
Characters. — Robust, opaque gray pollinose, black-bristly species with aborted wings. 
Head globular, occiput flattened hemispherical, not very bristly; two pairs of vertical bristles, one of 
diverging ocellar and one of cruciate preocellar; eyes widely separated, facets uniform, bare, the incision 
at the antennz strong, cheeks one-fourth the eye-height. Antenne three-jointed but the first joint very 
small, no setze beneath, third joint round, apically pubescent, with dorsal projection bearing the two- 
jointed geniculate arista, the basal joint of the arista long, solid, the outer joint slender and pubescent. 
Proboscis strong, very robust, inflexed, the palpi elliptical, setulose on the anterior surface and with a 
strong apical bristle. "Thoracic bristles strong, one humeral, one notopleural, two supraalar, three 
dorsocentral, one postalar. a double row of sparse acrostichal setulz, scutellum with two cruciate apical 
and two smaller lateral bristles; pleure not hairy. Abdomen with eight segments, the individual 
segments with a single pit on each side and with several larger ones at the extreme lateral edge, the last 
segment of the female compressed wedge-shape, with very short oval styles, in the male the abdomen is 
- very robust, the bristles becoming longer posteriorly, those of the seventh segment nearly as long as the 
last four segments; pygidium large, globose, closed, somewhat asymmetrical and twisted to the right, 
the small apical organs nearly dorsal. Legs short, robust, with black setule, those of the under side 
of the front femora and of the outer apical side of the hind femora more prominent, hind tibiz with two 
extensor bristles, one before the middle and one preapical, outer half of the hind tibiae with about six 
bristles irregularly placed, a pair of short apical bristles on the front tibie, tarsi flattened distally. 
Wings very small, triangular in outline, horizontally extended over the abdomen, reaching only to the 
third segment, the costal margin straight, stiff and minutely setulose, first vein ending near the apex of 
the wing, crossveins close together, the second basal cell a little shorter than the first, both extending to 
beyond the middle of the wing, no trace of an anal cell, hind margin entirely bare. 
Genotype : T. inchoata, Melander (Pl. 7, Fig. 71). Thetwo known species are inhabitants of 
sandy beaches on the Pacific coast of North America. "They are utterly unable to fly, but run nimbly 
over the sand and driftwood. 
Geographical distribution. 
1. Th. inchoata, Melander, Ent. News Philad. Vol. 17, p. 370, fig. (1906). — Pacific Coast of 
PI 7, Fig. 71. North America. 
2. Th. parallela, nov. sp. (1). Pacific Coast of 
North America. 
(1) Thinodromia parallela, nov. sp. — Length 2.5 mm. A larger species than zchoata differing in the structure 
ofthe wings. The wings are narrower in length, measuring three times as long as wide, the first five veins parallel, equally 
strong and reaching the wing-margin, the third vein ending at the extreme apex, the costa curving around the apex of the 
wing and continuing to beyond the end of the third vein. The costal setule are longer and obliquely erect. "The blackish 
color fills the apical third of the wing. In inchoata the wings are twice as long as broad ; the third vein bends forward so as 
to end in the first vein ; the second and fourth veins are obsolete; the costa becomes thin at the apex of the wing ; the costal 
