i. Posterior dorsocentrals inconstant and unequally developed; one pair of posterior inner dorsocentrals. _P. terrænovæ._ North America. _Protophormia_ Town. ii. Posterior dorsocentrals well developed, the inner dorsocentrals (acrostichals) unequally developed. _P. azurea_, _chrysorrhœa_, etc. Europe and America. _Protocalliphora_ Hough hh. Mesonotum not flattened behind the transverse suture; posterior inner and outer dorsocentrals inconstant and unequally developed. _P. regina._ Europe and America. _Phormia_ R. D. ee. Species more or less rufous or yellow in color. f. Anterior dorsocentrals wanting; first section of the R_{4+5} at most only bristly at the base, bend near apex of M_{1+2} rectangular, R_1 ends over the crossvein; fronto-orbital macrochæta absent; eyes of the male contiguous. _C. semiviridis._ Mexico. _Chloroprocta_ V. d. W ff. With another combination of characters. g. Body robust, of large size, abdomen elongate, not round; genæ with several ranges of microchætæ; vibrissal ridges strongly convergent; abdomen with well developed macrochætæ; costal spine usually absent; eyes of the male widely separated. [Illustration: 171. Stigmata of the larvæ of Muscoidea. Third instar. (_a_) Cynomyia cadaverina; (_b_) Phormia regina; (_c_) Chrysomyia macellaria; (_d_) Musca domestica; (_e_) Sarcophaga sp.; (_f_) Oestris ovis; (_g_) Gastrophilus equi; (_h_) Sarcophaga sp.; (_i_) Pegomyia vicina; (_j_) Protocalliphora azurea; (_k_) Hypoderma lineata; (_l_) Muscina stabulans. Magnification for f, g, and k, ×25; all others, × 50.] h. Peristome broad, pteropleural macrochætæ distinct; one or two sternopleurals; in the female a single orbital macrochæta; last abdominal segment without discal macrochætæ; hypopygial processes of the male with a long stylet; second abdominal segment of the female sometimes much elongate. A. LUTEOLA (fig. 86). Africa. The sub-genus _Chœromyia_ Roub. is included here. AUCHMEROMYIA B. B. hh. Peristome narrow; no pteropleurals, two sternopleurals; two orbitals in the female; second segment not elongate; the fourth with two well developed discal macrochætæ. B. DEPRESSA. Africa. BENGALIA R. D gg. With another combination of characters.