74 PROCEEDIXGS OF THE NATIONAL MUSEUM vol. 93 



(more noticeably so in male) ; some tendency exhibited, especially in the 

 specimens from loaf-rollers, for upper of two median anterolateral bristles 

 on midtibia to be less than one-half length of lower bristle. Female with 

 one strong reclinate prevertical, often with uppermost frontal bristle 

 reclinate, the females from Pyrausta nubttalis often with additional smaller 



preverticals 11. caesar (Aldrich) (p. 88) 



Parafrontal, face, and gena blackish-smoky-gray pollinose in male, silver gray 

 in female, with parafrontals becoming blacker toward vertex (parafrontal 

 never with a distinctive tawny or brassy tinge) ; hairs, at least in male, 

 larger and more profuse outside and below frontal bristles; front at nar- 

 rowest in male about 0.22 and in female about 0.31 head width; third seg- 

 ment of antenna in male three and in female two and one half times length 

 of second segment; arista thickened on basal one-third, penultimate segment 

 short, at most hardly longer than broad ; midtibia with at least two median 

 anterolateral bristles, the upper being more than half length of lower, 

 females especially with an additional small bristle above upper bristle. 

 Female with at least two strong reclinate preverticals located definitely 

 outside row of frontal bristles ; a darker species, not so heavily pollinose as 

 caesar, pollen of second abdominal segment confined more to the base and 

 sides 12. mitis (Meigen) (p. 90) 



12. Discal macrochaetae or bristles on both second and third abdominal segments 



either regularly or irregularly arranged 14 



No discal macrochaetae or bristles on second and usually lacking on third 

 abdominal segment 13 



13. Parafrontal silvery pollinose, blacker toward vertex; thorax and abdomen 



shining black, thinly silvery-gray pollinose at most ; midtibia with one 

 median anterolateral bristle: no discal bristles; first and fourth abdominal 

 segments shining black ; a little patch of dense hairs on the sides of the 



third and fourth segments (male only) 13. polita (Coquillett) (p. 90) 



Parafrontal golden-pollinose ; thorax and abdomen predominantly golden- 

 pollinose ; midtibia with two median anterolateral bristles; third segment 

 (in some females) varying from no discals to a pair of discal macrochaeiae 

 sometimes irregularly placed ; dorsum of all four segments golden-pollinose. 



14. helvina (Coquillett) (p. 91) 



14. Midtibia with one median anterolateral bristle, sometimes with a smaller addi- 



tional bristle above; third segment of antenna four or more times the length 



of second 17 



Midtibia with two or three median anterolateral bristles ; third segment of 

 antenna not over twice length of second 15 



15. Front at vertex one-fourth head width in male; hypopygium with inner 



forceps long and tapering l(i 



Front at vertex less than one-fifth head width in male and barely more than 

 one-fourth head width in female ; hypopygium with tip of inner forceps 

 curved backward, outer forceps about four-fifths length of inner forceps ; 

 9-12 15. epicydes (Walker) (p. 92) 



16. One reclinate prevertical bristle ; black, gray-pollinose species ; hypopygium 



with large inner forceps long, straight, and tapering, outer forceps wider, 

 four-fifths length of inner forceps; 12 mm. (male only) 



16. imitator, new species (p. 93) 

 Two reclinate prevertical bristles ; black, subshining ; very thinly gray- 

 pollinose species ; hypopygium with inner forceps similar to that of imitator 

 but more concave on outer side and not a great deal longer than outer 

 forceps ; 8.5 mm. (male only) 17. trichiosomae, new species (p. 94) 



