Handbook of Medical Entomology Part 41

gg. Third segment of the antenna furnished with a tooth or a distinct angular projection.

h. Hind tibiae ciliate with long hairs. S. W. and tropics.

_Snowiella_ and _Stibasoma_.

hh. Hind tibiae not ciliate.

i. Species of slender build, usually with a banded thorax and abdomen; third segment of the antenna slender, the basal prominence long; wings mostly with brownish markings. Tropic America.

_Dichelacera_ Macq.

ii. Species of a stouter build; third segment of the antenna stout, its basal process short (fig. 161b).

Many species, widely distributed TABa.n.u.s L.

dd. With another group of characters.

e. Squamae small, antennae variable, thinly pilose or nearly bare species, without distinct bristles; wing veins not crowded anteriorly, R_4 and R_5 both present, basal cells large; middle tibiae at least with spurs. LEPTIDae

f. Flagellum of the antenna more or less elongated, composed of numerous more or less distinct divisions. XYLOPHAGINae and ARTHROCERATINae.

ff. Antennae short, third segment simple, with arista or style; face small, proboscis short LEPTINae

g. Front tibiae each with one or two spurs, or if absent, then no discal cell. _Triptotricha_, _Pheneus_, _Dialysis_, _Hilarimorpha_.

gg. Front tibiae without terminal spurs, discal cell present.

h. Hind tibiae each with a single spur.

i. a.n.a.l cell open (fig. 163g); third antennal segment kidney-shaped with dorsal or subdorsal arista; first antennal segment elongate and thickened. About a dozen species have been described from the United States, of which at least one (S. PACHYCERAS) is known to be a vicious blood sucker. SYMPHOROMYIA Frauenf.

ii. a.n.a.l cell closed; third antennal segment not kidney-shaped. _Chrysopila_, _Ptiolina_, _Spania_.

hh. Hind tibiae each with two spurs.

i. Third segment kidney-shaped, the arista subdorsal; a.n.a.l cell closed. _Atherix_ Meig.

ii. Third segment of the antenna short and with terminal arista; a.n.a.l cell open _Leptis_ Fabr. Two European species of this genus have been accused of blood sucking habits, but the record seems to have been based upon error in observation.

ee. With another combination of characters. STRATIOMYIIDae, CYRTIDae, etc.

cc. Empodium bristlelike or absent.

d. Antennae apparently two segmented, with three-segmented arista, wings (rarely wanting) with several stout veins anteriorly, the weaker ones running obliquely across the wing (fig. 163h); small, quick running, bristly, humpbacked flies. Several genera; APHIOCHaeTA, PHORA, TRINEURA, etc. PHORIDae

dd. Flies with other characters.

e. No frontal lunule above the base of the antennae; both R_4 and R_5 often present; third segment of the antenna often with a terminal bristle. ASILIDae, MYDAIDae, APIOCERIDae, THEREVIDae, SCENOPINIDae, BOMBYLIIDae, EMPIDIDae, DOLICHOPODIDae, LONCHOPTERIDae.

ee. A frontal lunule above the base of the antennae; third segment of the antenna always simple, i.e., not ringed, usually with a dorsal arista; R_4 and R_5 coalesced into a simple vein.

f. A spurious vein or fold between the radius and the media, rarely absent; the cell R_{4+5} closed at the apex by vein M_1; few or no bristles on the body, none on the head; flies frequently with yellow markings. ERISTALIS (fig.

163i), HELOPHILUS, and many other genera. SYRPHIDae

ff. No spurious vein present.

g. Body without bristles; proboscis elongate and slender, often folding; front of both male and female broad.

CONOPIDae

gg. Bristles almost always present on head, thorax, abdomen and legs.

h. Arista terminal; hind metatarsus enlarged, sometimes ornamented, hind tarsus more or less flattened beneath PLATYPEZIDae

hh. Flies having a different combination of characters.

i. Head large, eyes occupying nearly the entire head; cell R_{4+5} narrowed in the margin; small flies.

PIPUNCULIDae

ii. Head and eyes not unusually large.

j. Squamae (tegulae, or calyptrae, or alulae) not large, often quite small, the lower one lacking, or at most barely projecting from below the upper one (antisquama); front of both male and female broad, the eyes therefore widely separated; posthumeral and intraalar macrochaeta not simultaneously present; thorax usually without a complete transverse suture; postalar callus usually absent; the connectiva adjoining the ventral sclerites always visible; hypopleural macrochaetae absent; last section of R_{4+5} and M_{1+2} with but few exceptions nearly parallel; subcostal vein often wanting or vestigial or closely approximated to R_1; the latter often short, basal cells small, the posterior ones often indistinct or wanting; vibrissae present or absent. ACALYPTRATE MUSCOIDEA

k. Subcosta present, distinctly separated from R_1 at the tip; R_1 usually ends distad of the middle of the wing; the small basal cells of the wing distinct.

l. A bristle (vibrissa) on each side of the face near the margin of the mouth. CORDYLURIDae, SEPSIDae, PHYCODROMIDae, HETERONEURIDae, HELOMYZIDae.

ll. No vibrissae present.

m. Head nearly spherical, cheeks broad and retreating; proboscis short; the cell R_5 closed or narrowed in the margin; legs very long; tarsi shorter than the tibiae. CALOBATA and other genera. MICROPEZIDae

mm. Flies with another combination of characters. RHOPALOMERIDae, TRYPETIDae, ORTALIDae, SCIOMYZIDae.

kk. Subcosta absent or vestigial, or if present, then apparently ending in the costa at the point where R_1 joins it; R_1 usually ends in the costa at or before the middle of the wing.

l. Arista long plumose, or pectinate above; oral vibrissae present; a.n.a.l cell complete; costa broken at the apex of R_1. DROSOPHILA, PHORTICA, and other genera. DROSOPHILIDae

ll. With another combination of characters.

m. The cell M and first M_2 not separated by a crossvein; a.n.a.l cell absent; front bare or only bristly above; usually light colored flies. HIPPELATES, OSCINUS, and other genera. (See also m m m.) OSCINIDae

mm. Cell M and cell first M_2 often separated by a crossvein; a.n.a.l cell present, complete, though frequently small; scutellum without spines or protuberances; oral vibrissae present; arista bare or short plumose; front bristly at vertex only; small dark flies.

PIOPHILA (fig. 99), SEPSIS and other genera.

SEPSIDae

mmm. The GEOMYZIDae, AGROMYZIDae, PSILIDae, TRYPETIDae, RHOPALOMERIDae, BORBORIDae and DIOPSIDae differ in various particulars from either the OSCINIDae and the SEPSIDae noted above.

jj. Squamae well developed, usually large, the lower one frequently projecting from below the upper one; both posthumeral and intraalar macrochaetae present; thorax with a complete transverse suture; postalar callus present and separated by a distinct suture from the dorsum of the thorax; front of the female broad, of the male frequently narrow, the eyes then nearly or quite contiguous; the connectiva adjoining the ventral sclerites either visible or not; hypopleural macrochaetae present or absent; subcosta always distinct in its whole course, R_1 never short. CALYPTRATE MUSCOIDEA[J]

k. Oral opening small, mouth parts usually much reduced or vestigial. This family is undoubtedly of polyphyletic origin but for convenience it is here considered as a single family. OESTRIDae.

l. The costal vein ends at the tip of R_{4+5}, M_{1+2} straight, not reaching the wing margin, hence cell R_5 wide open (fig. 163j); squamae small; arista bare; ovipositor of the female elongate. Larvae in the alimentary ca.n.a.l of horses, etc. GASTROPHILUS