FAM. EMPIDID/E 33 
38. Abdomen not surpassing the wings inlength . . . . . E. DERODACTYLUS, nov. sp. (1). 
Abdomen greatly surpassing the wings . . . . . . . E. LEPTOGASTER, nov. sp. (2). 
Geographical distribution. 
E. ardofeodes, nov. sp. Costa Rica. 
2. E. Bakeri, Wheeler & Melander, Biol. Centr.-Amer. Dipt. Vol. r, p. 372 Mexico. 
[1901] (Hiybos triplex, var. Bakeri). 
3. E. bavofeodes, nov. sp. New Hampshire. 
4. E. Coquilletti, nov. sp. North Carolina. 
5. E. crassipes, Fabricius, Syst. Antl. p. 146 [1805] (Hybos); Wiedemann, South America. 
Aussereurop. Zweifl. Ins, Pt. r, p. 539 [1828] (Hiybos); Bezzi, Nova 
Acta Kais. Naturf. Halle, Vol. 9r, p. 305 [1909] (Hybos). 
hind femora moderate, no bristles on upper posterior face, one extensor near knee, two on anterior face, ventral bristles 
normal; hind tibize simple. Stigma very faintly indicated, sections of fifth vein 3: r, fourth vein not much bent at posterior 
crossvein. 
Holotype, White Mountains, New Hampshire, H. K. Morison, collector, in U. S. National Museum. 
(i) Euhybos derodactylus, nov. sp. — Female. Length 5.5 mm. Occiput black, finely dusted with gray ; 
outer antennal joint two times long as broad, arista three times antennal length. Mesonotum polished, with purple lustre, 
posterior declivity very finely dusted, setula seriate, posterior dorsocentral developed, apical scutellars approximate, about 
six minute lateral hairs on each side; pleurz black. Abdomen long and slender, equalling the long wings, polished, the 
tergites with purple lustre, the eigth segment chitinized, short, tubular, the ninth or ovipositor lengthened, bulbous in the 
middle, hairs long and white at base, elsewhere very sparse and short. Anterior coxa brown, hind ones black, anterior legs 
yellow, last three joints of all tarsi black, middle tibia bullate at basalthird and bearing a small spur within, posteriorly 
ciliate, two basal joints of anterior tarsi extremely long and slender, together equal to their tibie, hind femora strongly 
clavate, with yellow base and abruptiy black club, eight strong bristles in outer flexor row, some short stout bristles under- 
neath near knee, inner flexor bristles more slender, a single extensor preapical bristle, hind tibia geniculate, arcuate, simple, 
yellow on basal three-fifths and black apically ; no flexor tibial bristles, three long slender extensor bristles on middle tibize, 
extremely long setze on anterior metatarsi, pulvilli of anterior legs more than twiceas longas hind ones. Halteres with long 
thin yellow stalk and black knob. Wings hyaline, veins thin and blackish, a strong blackish stigma filling end of mar- 
ginal cell, costal sections 1 : 0.15 : 0.18 : 0.05, first posterior cell decidedly tapering, sections of fourth vein subequal, of fifth 
vein r1 : 0.5. : 
Holotype, La Suiza de Turrialba, Costa Rica, November, 1922, Pablo Schild, ccllector. 
(2) Euhybos leptogaster, nov. sp. — Male. Length 7; mm. An extremely slender species proportioned as 
in the asilid genus Leftogaster. Black: eyes narrowly separated along the lengthened face; lastantennal joint top-shaped, 
the filiform arista nearly three times antennal length ; proboscis very short, broad, palpi narrow ; occiput cinereous-dusted, 
its sparse hairs long, fine and black. "Thorax dusted, with brown on mesonotum and with gray on pleurz, a small denuded 
spot in dorsocentral rows before base of wings, posthumeral area more densely coated, hairs sparse, posterior dorsocentral, 
twolateral and the apical scutellar pair distinct. Abdomen polished, remarkably thin, second to fourth segments tubular, 
each about five times as long as wide, segments six to eight shorter and dusted, genitalia consisting of two large, long, con- 
vex, distorted, black-hairy valves. Cox black, anterior legs yellowish, last two joints of all tarsi black, hind femora black 
except narrow knees, hind tibiz and tarsi luteous; first two joints of anterior tarsi very thin and long, together equalling 
their tibize, anterior pulvilli excessively long, twice the lengh of their claws, hind pulvilli one-half the length of their claws; 
hind femora with about ten strong spines in each of the flexor rows each arising from a low tubercle, a small spine above 
towards the knee, hind tibiae simple; excessively long setze present as follows: a pair near end of front tibiee, a pair at apex 
of front metatarsi, a flexor at basal third of middle tibize, two short extensor below middle knees, one at tip of middle tibize, 
one at base of middle metatarsi, one extensor near middle and a pair at apex of same joint. Halteres with thin pale stalk and 
black knob. "Wings hyaline, veins thin and brownish, no stigma, first vein short, ending before posterior crossvein, costal 
sections 1 : 0.6 : 0.3 : 0.1, third and fourth veins almost parallel, slightly converging, sections of fourth vein 1 : 1.2, of fifth 
vein 1 : o.6, pedicel of second and third veins very short. 
Female. Alternate bristles of anterior flexor row of hind femora reduced, there being five strong ones left, posterior 
reduced to three small bristles toward knee. Eighth abdominal segment corneous, bulbous on each side of base and contin- 
uing as a long flattened ovipositor. 
Two specimens, La Suiza de Turrialba, Costa Rica, Pablo Schild. "This curious species departs from the habitus of 
its congeners, but not sufficiently to be removed to a separate genus. "The lengthened abdomen, elongate anterior feet with 
their peculiar pulvilli, the pollinose thorax with developed dorsocentral bristles constitute a combination of characters 
disagreeing from other species of Eu&ybos. The nearly obliterated face, short proboscis and chitinized ovipositor would 
place the species in Euhybos rather than in Hybos, 
