NO. I BLACK FLIES OF GUATEMALA — DALMAT 73 



White-pruinose bands not in form of comma ; black hairs not longer in prescu- 

 tellar region than on rest of mesonotum ; yellow scalelike hairs well distrib- 

 uted on mesonotum ; prealar cluster composed of yellow hairs only ; abdomi- 

 nal segments 3-8 with at least some yellow coloration ; calcipala not passing 

 pedisulcus 4 



4. Ri with spines along its distal half, at most with one hair ; tergites of abdomi- 



nal segments 4-8 velvety brown ; hairs on first abdominal segment black. 



dozmisi Vargas, Martinez, and Diaz 

 Ri with both spines and hairs along its distal one-half to two-thirds ; tergites 

 of abdominal segments 4-8 with some yellow coloration; hairs on first ab- 

 dominal segment yellow 5 



5. Longitudinal band of white pruinosity on either side of midline with its borders 



almost parallel, hardly expanded at anterior end; scalelike hairs on meso- 

 notum very short; calcipala not quite reaching pedisulcus. 



samboni Jennings 

 Longitudinal band of white pruinosity on either side of midline expanded ante- 

 riorly and tapered posteriorly to form a definite triangle ; scalelike hairs on 

 mesonotum long and narrow ; calcipala reaching pedisulcus. 



colvini Dalmat 



6. White-pruinose band on either side of midline of mesonotum in form of elon- 



gated triangle, the base of which is on the anterior margin and the apex ex- 

 tending posteriorly to fuse with the white pruinosity of the prescutellar 

 region; scalelike hairs on mesonotum dark brown in central region from 

 anterior margin to prescutellar area, golden yellow on other parts ; Ri with 

 both spines and hairs on its distal half ; trochanter and femur of hind leg 

 completely black; calcipala almost reaching pedisulcus which is situated 

 one-third distance from base of second hind tarsal segment ; approximate 



length of male 3.0 mm vcracriizamini Vargas, Martinez, and Diaz 



White-pruinose band on either side of midline of mesonotum in form of broad 

 triangle, the apex of which extends posteriorly only one-third the distance 

 to the prescutellar region; scalelike hairs on mesonotum all golden yellow; 

 Ri with spines on its distal half and with at most two hairs ; trochanter of 

 hind leg tan, the femur black with a basal tan ring ; calcipala well removed 

 from pedisulcus which is situated at middle of second hind tarsal segment ; 

 approximate length of male 2.0 haenmtopotum Malloch 



SPECIES OF THE SUBGENUS SIMULIUM, BASED ON EXTERNAL 

 CHARACTERS OF THE MALES 



1 . Mesonotum lacking scalelike hairs 2 



Alesonotum with yellow to golden scalelike hairs 3 



2. Mesonotum orange-yellow ; Ri completely pilose, the distal half with spines as 



well as hairs ochraceum Walker 



Mesonotum black ; distal half of Ri with spines only, the basal half bare. 



metallicum Bellardi 



3. White-pruinose band along periphery of mesonotum without interruption, in- 



dented toward center of dorsum where it passes the middle of anterior 



margin tricornis De Leon 



White-pruinose band interrupted at middle of anterior margin of meso- 

 notum 4 



