m. Posterior crossvein (m-cu) wanting; wings smoky or with clouds. Europe. G. PECORUM
mm. Posterior crossvein (m-cu) present, at least in part.
n. Wing hyaline with smoky median cross band, and two or three spots; posterior trochanters with hook in the male and a prominence in the female. World wide distribution. G. EQUI.
nn. Wings without spots.
o. Posterior crossvein (m-cu) distad of the anterior crossvein (r-m); legs, particularly the femora, blackish brown.
Europe and North America. G.
HaeMORRHOIDALIS
oo. Posterior crossvein opposite or proximad of the anterior crossvein. Europe and North America. G. NASALIS
ll. The costal vein ends at the tip of M_{1+2}, M_{1+2} with a bend, the cell R_5 hence much narrowed in the margin, or closed.
m. Proboscis geniculate, inserted in a deep slit; female without extricate ovipositor; arista either bare or plumose; squamae large; facial grooves approximated below.
n. Arista bare, short. Larvae in rodents.
Tropic America. _B. princeps_. _Bogeria_ Austen
nn. Arista pectinate above.
o. Tarsi broadened and flattened, hairy, a.n.a.l lobe of the wing large. Larvae in rodents. A number of American species.
_Cuterebra_.
oo. Tarsi slender, not hairy; a.n.a.l lobe of the wing moderate. Larvae in man and other mammals. Tropic America. D.
CYANIVENTRIS. DERMATOBIA Br.
mm. Mouth parts very small, vestigial; arista bare.
n. Facial grooves approximated below, leaving a narrow median depression or groove.
o. Cell R_5 closed and petiolate, body nearly bare. Larvae in the nasal cavities of the smaller Ungulates. The sheep bot fly. O. OVIS. Widely distributed OESTRUS L.
oo. Cell R_5 narrowly open, body hairy.
Larvae parasitic on deer. Europe and America. _Cephenomyia_ Latr.
nn. Facial grooves far apart, enclosing between them a broad shield-shaped surface; squamae large; female with elongate ovipositor. Larvae hypodermatic on Ungulates HYPODERMA Clark
o. Palpi wanting; tibiae thickened in the middle.
p. Hair at apex of the abdomen yellow; legs including femora yellowish brown.
H. DIANA
pp. Hair at the apex of the abdomen reddish yellow. Europe and America.
q. Tibiae and tarsi yellow; femora black.
H. LINEATA
qq. Legs black with black hair; tips of hind tibia and tarsi yellowish brown. H. BOVIS
oo. Palpi small, globular; tibiae cylindrical, straight. On reindeer. _O.
tarandi_ _Oedemagena_ Latr.
kk. Oral opening of the usual size; mouth parts not vestigial.
l. Hypopleurals wanting; if three sternopleurals are present the arrangement is 1:2; conjunctiva (fig. 161c) of the venter usually present; if the terminal section of M_{1+2} is bent it has neither fold nor appendage (ANTHOMYIIDae of Girschner).
m. Sternopleurals wanting; M_{1+2} straight toward the apex, costa ends at or slightly beyond the tip of R_{4+5}; mouth parts vestigial. GASTROPHILINae. See OESTRIDae
mm. Sternopleurals present, if rarely absent then differing in other characters.
n. Caudal margin of the fifth ventral abdominal sclerite of the male deeply notched on the median line usually to beyond the middle; abdomen often cylindrical or linear; abdomen often with four to eight spots; eyes of the male usually widely separated; sternopleurals three, arranged in an equilateral triangle; subapical seta of the hind tibia placed very low; M_{1+2} straight; a.n.a.l vein abbreviated; wings not rilled.
_Caenosia_, _Caricea_, _Dexiopsis_, _Hoplogaster_, _Schnomyia_, etc.
(CNOSINae)[K]. ANTHOMYIIDae in part
nn. Caudal margin of the fifth ventral abdominal sclerite of the male incurved, rarely deeply cleft, rarely entire, in a few genera deeply two or three notched; M_{1+2} straight or curved; abdomen usually short or elongate oval; sternopleurals, if three are present, arranged in the order 1:2 in a right triangle. (MUSCINae-ANTHOMYIINae of Girschner)
o. M_{1+2} straight, hence cell R_5 not narrowed in the margin. ANTHOMYIIDae in part
p. Underside of the scutellum more or less spa.r.s.ely covered with fine hairs; a.n.a.l vein nearly always reaches the hind margin of the wing; extensor surface of the hind tibiae with a number of stout setae; squamae often small and equal. ANTHOMYIA, _Chortophila_, _Eustalomyia_, _Hammomyia_, _Hylemyia_, _Prosalpia_, _Pegomyia_, etc. HYLEMYINae-PEGOMYINae
pp. Underside of the scutellum bare; a.n.a.l vein does not reach the wing margin.
q. First a.n.a.l vein short, second a.n.a.l suddenly flexed upwards; hind tibiae each with one or two strong setae on the extensor surface. FANNIA (= HOMALOMYIA), _Clomyia_, _Choristoma_, _Euryomma_, _Azelia_, etc. FANNINae-AZELINae
qq. a.n.a.l veins parallel or divergent.
r. Setae on the exterior surface of the hind tibiae wanting (except in _Limnaricia_ and _Cnosites_), lower squama not broadened to the margin of the scutellum.
_Leucomelina_, _Limnophora_, _Limnospila_, _Lispa_, _Mydaea_, _Spilogaster_, etc.
MYDaeINae-LIMNOPHORINae
rr. One (rarely more) seta on the extensor surface of the hind tibia; squamae usually large and unequal. HYDROTAEA, _Aricia_, _Drymeia_, _Ophyra_, _Phaonia_ (= _Hyetodesia_), _Pogonomyia_, _Trichophthicus_, etc. ARICINae
oo. M_{1+2} curved or bent, hence the cell R_5 more or less narrowed in the margin.
(MUSCINae). MUSCIDae in part. See page 303 for generic synopsis.
ll. Hypopleurals present; when three sternopleurals are present the arrangement is 2:1 or 1:1:1. (TACHINIDae of Girschner)
m. Conjunctiva of the ventral sclerites of the abdomen present, frequently well developed, surrounding the sclerites.
n. Mouth parts vestigial. OESTRIDae. See page 297 for generic synopsis.
nn. Mouth parts well developed.
o. M_{1+2} straight, hence cell R_5 wide open in the margin; costa ending at the tip of R_5; three sternopleurals present; antennal arista plumose.
_Syllegoptera_. Europe.
(SYLLEGOPTERINae). DEXIIDae in part