46 Proceedings of the Biological Society of Washington. 



thirds to three-fourths width of clypeus. Facio-orbitals in row of very 

 fine and short hairs only. Cheeks hardly one-half eye-length. ,Post- 

 acrostichals vestigial. Costal spine strong. First vein bristled less than 

 half-way, third to or nearly to small crossvein. No median macrochaetae 

 on second abdominal segment, weak median marginals on third, weak 

 marginal row on anal segment. First hypopygial tergite forming wide 

 vertical slit bordered with decussate bristles. The male is not known. 



The species is founded on two females taken by Mr. F. Knab at Cor- 

 doba, Veracruz, April 1 and 10, 1908. It lacks preacrostichals and other- 

 wise fails to agree with Wulp's description of villipes. Named in honor 

 of Mr. F. Knab. 



Holotype, No. 20,948 U. S. N. M. 



Acridiophaga new genus. 



Genotype, Sarcophaga aculeata Aldrich, op. cit., 143-4. 



Differs from Sarcophaga as follows: Vibrissal axis not over three-fifths 

 head-height, shorter than antennal axis. Clypeus broader than length 

 of third antennal joint, rather shortened ; epistoma broad, well projected 

 below, nearly in plane of clypeus. Facialia rather flattened, the vibrissal 

 angles considerably narrowing the facial plate. Proboscis about two- 

 thirds head-height. Male vertex less than one-half eye, that of female 

 little over three-fourths eye. Frontals diverging obliquely one or two 

 bristles below base of antennae. Outer verticals not developed in male. 

 Male with two reclinate fronto-orbitals. Frontalia narrowing posteriorly 

 in both sexes, narrower than one parafrontal in female. Parafacialia 

 over half width of clypeus, rather thickly hairy on orbital half. Facio- 

 orbitals represented by four or five bristly hairs a little longer than the 

 others. Cheeks a little less than half eye-length. Three strong post- 

 suturals. Three or four preacrostichals. Squamae rather longer than 

 broad. None of male tibiae villous. Median marginals of second ab- 

 dominal segment weak or vestigial, weak marginal row on third and anal 

 segments. Male hypopygium rather small. First hypopygial tergite of 

 female entire ; theca ending in spatulate lobes. 



This genus includes many species, most of which are particularly para- 

 sitic on Acridiidae, ranging from the western States through tropical 

 America to the Argentine. 



Metoposarcophaga new genus. 



Genotype, Sarcophaga pachyprocta R. R. Parker, 1916, Journ. N. Y. 

 Ent. Soc, XXIV, 171-5. 



Differs from Sarcophaga as follows: Lower profile of head short, the 

 vibrissal axis strikingly less than antennal axis. Clypeus rather nar- 

 rowed and elongate, carina more or less distinct. Epistoma projecting 

 only a little, somewhat warped. Proboscis hardly two-thirds head-height. 

 Arista not very long-plumose. Male vertex three-fourths eye, that of 

 female fully as wide as eye. Frontals diverging one bristle below base of 

 antennae. Outer verticals strong in male. Frontalia appreciably nar- 



