520 



latter in having the eyes bare. The distinction between OrtJwcladius 

 and Psectrocladiiis lies in the absence of pulvilli and empodia in the 

 former and their presence in the latter. It is a rather unsatisfactory 

 character, but still an appreciable one, and seems to be coordinated 

 with the difference in color. 



The early stages are not known. 



Key to Species 



1. Yeiy small species, not exceeding 1 mm. in length; venation as in 



Figure 1, Plate XXXIX 1. sordens. 



— Larger species, over 2 mm. in length 2. vernalis. 



I. PsECTROCLADius soRDExs Johauuscn 



Orthocladiits sordens Jolianusen, Bull. 86, N. Y. State Mus., 1905, p. 272. 



Female. — Yellow, opaque. Head yellow, apical joint of antennae 

 and the palpi subfuscous. Mesonotum with three brown vitta? ; sterno- 

 pleura and a spot slightly in front of wing-base brown ; scutellum yel- 

 low ; postnotum dark brown. Abdomen with a median fuscous fascia, 

 which is generally rather broad and occasionally extends to apex of 

 abdomen. Legs and halteres yellow\ Wings clear, veins pale yellow. 



Pronotum distinct, not broad, linear on upper third and discontin- 

 ued distinctly before upper margin of mesonotum, the latter slightly 

 protruding anteriorly. Fore tarsi with basal joint half as long as 

 tibia (5 : lo), fourth tarsal joint of all legs shorter than fifth. Third 

 vein not reaching beyond beginning of apical curve; cross vein oblique, 

 one third from wing-base ; cubitus forking distinctly beyond cross 

 vein, posterior branch sinuate. (PI. XXXIX, Fig. 7.) 



Length, .75-1 mm. 



Illinois locality, Urbana. A large series of females taken by the 

 writer at a State Laboratory desk-light May 4, 1914. 



Originally described from Ithaca, N. Y., by Johannsen, who sug- 

 gested at the time that two mutilated specimens from South Dakota 

 which he had before him might also belong to this species. 



The male and early stages are undescribed. 



2. PsECTROCIvADIUS VERNAEIS, n. sp. 



Male. — Yellow, slightly shining. Head yellow; scape of antennae 

 black, flagellum brown, yellowish at base, plumes brownish, paler at 

 bases; palpi fuscous at apices. Mesonotum with shining brownish 

 black vittai, pleural spots and pronotum black or brownish black. Ab- 

 domen brown, hypopygium yellowish. Legs yellow; apices of tarsi 



