120 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 113 



Allotype: In INHS: Havana, 111., Chautauqua Park, Apr. 29, 1914. 



Coloration similar to holotype; wing spots heavier, membrane more 

 densely haired; stem of M between r-m and m-cu very short, only 

 about one-half as long as in males; pronotum more strongly produced 

 anterior^; dorsolateral bristles single to just anterior to scutellum 

 where row is doubled for about 4 bristles. 



Wing length 3.28 mm.; fore leg ratio 0.80; venarum ratio 1.10; 

 hind leg ratio 0.96. 



Paratypes from Illinois: In INHS: 4 males, 3 females, Havana, 

 Apr. 27, 29, 1914; 1 male. Quiver Lake, Havana, Sept. 19, 1895, 

 Hart, Newberry, Hempel; 1 female, Momence, July 17, 1914; 1 male, 

 2 females, St. Joseph, June 9, 1915; 1 female, Urbana, Sept. 5, 1914; 

 1 male, Vergennes, Aug. 12, 1914. 



Paratypes from Texas: In INHS: 1 female. Lake Lomalta, Sept. 27, 

 1910. 



Paratypes from Louisiana: In USNM, L^CLA, JES: 9 males, 2 

 females, Natchitoches, Chaplain's Lake, Feb. 4, 5, 1957, reared, 

 JES; 1 male, Natchitoches, pool near Northwestern State College 

 Dairy, Oct. 22, 1954, reared, JES; 2 males, Natchitoches, U.S. Fish 

 Hatchery, March 21, 22, 1960, reared, JES. 



Paratypes from Alabama: In Dendy, JES: 9 males. Auburn, 

 June 6, 1956, J. S. Dendy; 1 male. Auburn, June 8, 1956, J. S. Dendy; 

 1 male, Auburn, June 23, 1955, J. S. Dendy. 



Males: Wing length, range 2.44-3.07; mean 2.78 mm. (7); fore leg 

 ratio, range 0.84-0.98; mean 0.91 (8); hind leg ratio, range 0.88-1.08; 

 mean 0.97 (7) ; antennal ratio, range 2.01-2.43 ; mean 2.22 (7) ; venarum 

 ratio, range 1.00-1.08; mean 1.04 (3). 



Females: Wing length 2.96, 3.33 mm. (2); fore leg ratio 0.74, 0.88 

 (2) ; hind leg ratio 0.90 (1) ; venarum ratio 1.02, 1.08 (2). 



This species most closely resembles T. imperialis, new species, from 

 which it can be distinguished by the distinctively different genitalia 

 and by having the superior pronotal margin only slightly produced 

 apically. It is distinguished from the other North American species in 

 the key which follows. 



Key to North American Species of Tanypus 



1. Tubercle of mesonotum very small and inconspicuous, concolorus with 

 remainder of mesonotum or only slightly lighter in color; general body 



color dark; palpi 4-segniented 2 



Tubercle conspicuous, yellow or yellowish-white, strongly contrasting with 

 remainder of brown to dark brown mesonotum; occasionally tubercle 

 infuscate yellow; body with yellowish ground color; palpi 3-segmented . 4 



