ABT. 12 KEYS TO SAPROMYZIDAE MALLOCH AND McATEE. 17 



brown spots and dots, the greater part of abdomen dark brown, with pale 

 gray pruiuose spots at bases of bristles and setulae; thorax with four 

 pairs of dorsocentrals and four or five pairs of strong acrostichals, 



stictica Loew." 

 Wings clear, or at least without small clear spots on a dark ground 2 



2. Wings with the anterior, or costal, half, and the cross-veins browned ; 



thorax quadrivittate with brown, and with three pairs of dorsocentrals and 

 only one. prescutellar, pair of strong acrostichals; second costal division 

 less than half as long as first; one genal hair much longer and stronger 



than the others umbrosa Loew. 



Wings entirely hyaline; thorax with one pair of acrostichals V, 



3. Frons wholly glossy black, sometimes yellowish on anterior margin ; thorax 



and abdomen wholly black, shining, the former with four pairs of 

 dorsocentrals; face glossy black in center; second costal division a little 



less than half as long as first 4 



Frons not wholly glossy black, usually some part of it yellowish and 

 except in the entirely yellow species with distinct pruinescence ; if 

 largely or entirely shining black, there are only three pairs of dorso- 

 centrals ; thorax with two to four pairs of dorsocentrals 5 



4. Face and frons highly glossy, without pruinescence ; third anteunal segment 



at least four times as long as wide, not tapered to apex ; longest hairs on 

 arista decidedly longer than its basal diameter; acrostichals between 



dorsocentrals in two series quadrisetosa Thomson, variety. 



Face with distinct gray pruinescence below antennae; third antennal seg- 

 ment not over 2.5 times as long as broad, tapered apically ; longest hairs 

 on arista not longer than its basal diameter ; acrostichals between dorso- 

 centrals in four series nigerrima Melander (=blaisdelli Cresson). 



Face with distinct gray pruinescence below antennae; third antennal seg- 

 ment at least three times as long as broad, tapered apically ; longest hairs 

 on arista longer than its basal diameter; acrostichals between dorso- 

 centrals in four series— quadrisetosa Thomson (=vanduzeei Cresson?). 



5. Thorax with four pairs of dorsocentrals and distinct brown vittae; ab- 



domen with brown doi-sal spots; second costal division much shorter 

 than half as long as first 'j 



Thorax with two or three pairs of dorsocentrals; second costal division 

 almost or quite half as long as first 10 



Thorax with four pairs of dorsocentrals, and without vittae; abdomen 

 largely fuscous, without dorsal spots ; second costal division fully half as 

 long as first ; legs entirely yellow ; a large portion of third antennal seg- 

 ment and the palpi fuscous fusciventris Malloch. 



6. Fore femur without a comblike series of minute setulae between middle 



and apex on anteroventral surface ; bristles on posterior margins of 

 dorsal abdominal segments not set in black or brown spots; no dark 



spot in front of mesonotal suture laterad of the outer vitta 7 



Fore femur with a comblike series of minute setulae between middle and 

 apex on anteroventral surface ; bristles on posterior margins of 

 dorsal abdominal segments set in black or brown spots ; a brown or 

 fuscous spot in front of suture on mesonotum laterad of the outer 

 vitta 9 



* See p. 25. This is now placed in a new genus but because of similarity to species of 

 Sapromyza is included in the above Iie.v. 



