450 



yellow ; mid and hind tibise with a black apical comb ; apical joint of all 

 tarsi brownish. Hairs on legs and body w^hitish. 



Hairs on spaces between the thoracic vitt?e and on central line long 

 and soft, those in front of wing-base not numerous; scutellar hairs 

 long and soft. Abdomen slightly broadened from middle to apex of 

 penultimate segment, last segment much narrower than the preceding 

 segment and equal to the width of hypopygium basally. Basal joint of 

 fore tarsus one fifth longer than fore tibia; the apical half of basal and 

 whole of second joint of fore tarsus with long hairs on the posterior 

 surface; mid and hind legs with rather long soft hairs. Posterior 

 branch of radius and media reaching wing-margin at about the same 

 distance from wing-tip before and behind respectively (PI. XXXIX, 

 Fig. 4) ; cubitus forking slightly beyond the vertical line of the cross 

 vein. 



Female. — Similar in color to the male, except that the antennae 

 are almost entirely greenish yellow, the apical joint only being brown- 

 ish. 



The legs differ from those of the male in being much shorter- 

 haired, the fore tarsus being devoid of long hairs ; the tarsal propor- 

 tions are the same in both sexes. Wings broader than in male, and the 

 cubitus forks almost directly below the cross vein. 



Length, 5-6.5 mm. 



Illinois localities: Illinois River at Havana, April-June, 1914. 

 Hundreds of larvae of this species were obtained from a clump of 

 Ccratophylhmi dredged from the bottom of Thompson's Lake, Ha- 

 vana. These were readily reared in vials in the Laboratory, and the 

 descriptions herewith given are based on the series thus obtained. The 

 immature stages have not been previously described. 



Originally described from Europe. C. W. Johnson has recorded 

 it from Florida. 



30. Chironomus pskudoviridis, n. sp. 



This species resembles viridis so closely that it is only necessary to 

 indicate the points of difference between them. 



Male. — The mesonotum has generally distinct whitish pruinescence 

 between the vittae, wdiich is absent in viridis; the fore tibia is slightly 

 longer than the basal joint of the tarsus ; the cubitus forks slightly dis- 

 tad of the cross vein ; and the third vein ends considerably farther 

 from the apex of the wing (PI. XXXIX, Fig. i). Hypopygium as in 

 Figure 2, Plate XXXIII. 



Female. — Similar to the male in color. 



