FUNGUS GNATS OF NORTH AMERICA. 65 



Tabic of species. 



Males. 

 a. Curvature of Rs conspicuous, the'' ratio of the maximum normal of 

 the chord to the chord itself 4.5% or more, and the ratio of 

 ■\.^ a to b, .65 or less. 



b. FoTe' metatarsus 1.15 or more longer than the tibia. 



c. Curvature of Rs moderate (4.5%), fork of cubitus noticeably 

 distad of base of Rs (Fig. 159) ; hypopygium with two of 

 the 3 pairs of appendages each tipped with a black spine. 



I. perspictia n. sp. 

 cc. Curvature of Rs 7.i7( or over; fork of cubitus but slightly 

 distad of base of Rs. 

 d. Hind margins of abdominal segments yellow ; hypopygium > 

 (Fig. 32). 2. umbratica. fi'^ 



(Id. Yellow marking of abdominal segments, when present, con- 

 fined to the anterior margin; h3'popygium (Fig. 2>i)- 



3. nugax n. sp. 

 bb. Fore metatarsus shorter than the tibia; hypopygium (Fig. 34). 



4. nexa n. sp. 

 aa. Curvature of Rs not conspicuous, ratio of maximum normal of the 



chord to the chord 4% or less, and the ratio of a to b, .70 or more, 

 b. Hind margins of abdominal segments yellow and the two larger 

 pairs of appendages of hypopygium broad, lobular, 

 c. Fore metatarsus over 1.25 tibia in length; curvature of Rs 

 moderate (Fig. 163) ; hypopygium (Fig. 35). 



5. ahrupta n. sp. 

 cc. Fore metatarsus less than 1.12 tibia in length, curvature of 

 Rs slight (Fig. 16-I) ; hypopygium (Fig. 36). 



6. canaVicula n. sp. 

 bb. Abdomen unicolored, black or yellow or hind margins of ab- 

 dominal segments dark, or hypopygium of different structure, 

 c. Yellow species, darker markings on thorax and abdomen pale 

 brown, 

 d. Each branch of longer forceps with curved branch on 

 inner side (Fig. 39). 9. satiate n. sp. 



dd. Ventral sclerite of hj^popygium, large, quadrangular 

 (Fig. 38a). 8. quadrata n. sp. 



cc. Thoracic and abdominal markings dark brown. 



d. Fore metatarsus about 1-8 longer than the tibia; each limb 

 of the longer forceps either with distinct branch near 

 apex or wide lobe at base, 

 e. Thorax and abdomen with considerable yellow. 



f. Smaller species, 3 mm in length : each limb of longer 

 forceps with curved branch on inner side; 

 (Fig 39). g. satiata n. sp. 



ff. Larger species, over 4 mm in length. 



g. Limbs of both forceps forked (Fig. 41). 



10. nugatoria n. sp. 



