74 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 125 



4. Ri with spines and hairs on distal half 5 



Ri with only spines on distal half johbinsi Vargas, Martinez, and Diaz 



5. A single hair emerging midway between the most basal spine on Ri and the 



origin of R2+3, situated more than twice as far from the basal spine as the 

 distance between any other two spines or spines and hairs on Ri; golden- 

 yellow scalelike hairs over entire mesonotum; coxa and basal half of tro- 

 chanter of leg I, as well as basal half of trochanter of leg 2 yellow; calci- 

 pala of hind basitarsus reaching pedisulcus. 



parrai Vargas, Martinez, and Diaz 

 No hair between most basal spine on Ri and origin of R2+3; golden-yellow 

 scalelike hairs lacking on middle of dorsum; all coxae and trochanters 

 black ; calcipala of hind basitarsus not reaching pedisulcus. 



jacumbae Dyar and Shannon 



GENERA, BASED ON FEMALE CHARACTERS 



1. Pedisulcus present Simulium Latreille, 1802 



Pedisulcus absent 2 



2. Discal cell present; Cu2 arcuate; relation of length of basitarsus to that of 



segments 2-5 taken together 4-5:1; calcipala normal ; claw of hind tarsus 

 with heel strongly recurving apically, with very large lancelike structure 



emerging at base ; head normal Cnephia Enderlein, 1921 



Discal cell absent, at times barely indicated ; Cm straight, relation of basitarsus 

 to tarsal segments 2-5, 8-9 : i ; calcipala extremely long and broad ; claw of 

 hind tarsus with heel not retrorse, with shorter, narrower projection emerg- 

 ing beyond heel ; head greatly elongated anteriorly. 



Gigantodax Enderlein, 1925 



SPECIES OF THE GENUS CNEPHIA, BASED ON EXTERNAL 

 CHARACTERISTICS OF THE FEMALES 



1. Mesonotum clothed with numerous silver-colored, scalelike hairs as well as a 



few yellow hairs of same type ; tergites of abdominal segments clothed with 



white hairs aguirrei Dalmat 



Mesonotum clothed with golden-colored hairs ; tergites of abdominal segments 

 with black or brown hairs only 2 



2. Mesonotum with 3 longitudinal stripes of gray pruinosity, always visible al- 



though contrast not very sharp; cornuae of buccopharyngeal apparatus 



broad, sclerotized only along outer margins roblcsi (De Leon) 



Mesonotum with no longitudinal stripes differentiated; cornuae of buccopha- 

 ryngeal apparatus sharply pointed and well sclerotized. 



pacheco-lunai (DeLeon) 



SPECIES OF THE GENUS GIGANTODAX, BASED ON EXTERNAL 

 CHARACTERISTICS OF THE FEMALES 



All legs brown, with very little color variation in the form of bands ; relation 

 of basitarsus to second tarsal segment 8.1 : i ; buccopharyngeal apparatus 

 with wide, bifurcate, sclerotized cornuae aquamarensis (De Leon) 



Legs with variable color patterns ; relation of basitarsus to second tarsal seg- 



