AGROMYZID LEAF MINERS — FRICK 423 



31. Acrostichal setae in two rows 32 



Acrostichal setae in four to eight rows 33 



32. Third antennal segment subcircular (fig. 160); first dorsocentral seta about 



twice as far from the transverse suture as is the second .... melanella 

 Third antennal segment subrectangular, longer than wide (fig. 159); first and 

 second dorsocentral setae about equidistant from the transverse suture. 



marginalis 



33. Acrostichal setae in four or five rows 34 



Acrostichal setae in six to eight rows (see also couplet 18) ilicis 



34. Intraalar row with not more than 16 setulae anterior to and not more than 



five posterior to the transverse suture; abdomen mostly dark 35 



Intraalar row with about 24 setulae anterior to and about 12 posterior to the 

 transverse suture; abdomen mostly yellow bicolor 



35. Forefemur distally yellow to reddish brown; wing veins basally yellow to light 



brown; wing length not exceeding 2.25 mm 36 



Forefemur entirely black; wing veins basally black; wing length 2.5 to three 

 nam nigrinervis 



36. Acrostichal setae extending posteriorly to the third dorsocentral .... 37 

 Acrostichal setae extending posteriorly to the fourth dorsocentral .... 38 



37. Eye, viewed in profile, with length at most three-fourths the eye height; 



mesonotum dull brownish black gregaria 



Eye, viewed in profile, with length subequal to eye height; mesonotum dull 

 bluish black periclymeni 



38. Forefemur distally reddish brown; mesonotum black, dull grayish pollinose. 



persicae 

 Forefemur distally yellow; mesonotum brown, dull bluish pollinose . ilicicola 



39. Head with one or two upper-orbital setae; one or two lower-orbitals; wing 



length up to 2 mm 40 



Head with one upper-orbital seta; three lower-orbitals; wing length at least 

 3 mm nigripennis 



40. Intraalar row with at least three setulae posterior to the transverse suture; 



inner postalar about one-half as long as the outer 41 



Intraalar row with none to one setula posterior to the transverse suture; inner 

 postalar small, up to one-third the length of the outer, or absent. 



minuscula 



41. Forefemur distally brown; wing with second costal .section about 1.5 times as 



long as the fourth (fig. 145) centralis 



Forefemur distally yellow; second costal section at least two times as long 

 as the fourth (fig. 158) loewii 



Phytomyza affinalis Frost 



Phytomyza affinalis Frost, Mem. Cornell Univ. Agr. Exp. Sta., vol. 78, p. 84, 1924. 



The holotype male is in the U. S. National Museum (No. 50025). 

 This species has the frons yellow, mesofacial plate dark, third antennal 

 segment, mesonotal margins, scutellum, and femora dark, and both 

 upper-orbitals of equal length and strength. It differs from Phytomyza 

 atricomis in having about 14 acrostichals in two rows and the head 

 bearing three lower-orbitals and a wide gena (fig. 139). The type 

 series is from Saskatchewan. 



