445 



to the group which includes dccorus, viridicollis, and others, which 

 have the ventral blood-gills long and the first lateral tooth of labium 

 much shorter than median and second lateral. It is not possible to as- 

 sociate definitely any larva from the Illinois River collections with that 

 described by Weyenbergh, as his description is very unsatisfactory, but 

 the larva described below is the only one that agrees in general appear- 

 ance with that described by him, and occurring, as it does, in immense 

 numbers in the places where tcntans imagines do, it m^ay, I believe, be 

 assumed with a degree of certainty that it belongs to that species. 



Larz'ii*. — Length, 24-27 mm. Blood-red. General appearance as 

 in Figure 2, Plate XXXII ; labium as in Figure 9, Plate XXIX ; labial 

 papillcT as in Figure 10, Plate XXIII; ventral blood-gills four in num- 

 ber, very long; dorsal blood-gills large; dorsal anal tufts consisting 

 each of about six hairs, basal papilhe hump-like, not in the form of 

 stalks. 



The pupa has not been distinguished by the writer from that of 

 fcrrugincoiittatus by any structural character owing to the absence of 

 reared imagines. 



The species was originally described from Europe, and has been 

 recorded from New York, Idaho, South Dakota, Utah, and Iowa. I 

 have seen it from Wisconsin. 



Var. pallidiz'ittafus. n. var. 



This variety, which is mentioned by Van der Wulp, has not been 

 given a name by means of which it may be distinguished from the type 

 so far as I can discover. Some specimens taken at light at Flag Lake, 

 near Havana, August 6, 1896, and at the same place June 29, 1897, 

 differ from the type form in being smaller, averaging about 7 mm., 

 and much paler, the thorax and abdomen being yellowish, the former 

 with ferruginous vittae and the latter with fuscous suffusion except at 

 base ; the legs are decidedly paler, the dark markings reduced to mere 

 rings at apices of tibiae and of the first two tarsal joints, while the 

 apical three joints are browned. The antennal plumes are also much 

 paler than in the type form. 



This is probably the summer form of this species. 



Type locality, Havana, 111., August 7, 1895 (E- B. Forbes), and 

 August 8, 1896(0. A. Hart and C. C. Adams). 



*This is "Chironomiis larva (4) " mentioned by Garman in Bull. 111. State Lab. 

 Nat. Hist., Vol. 3, Art. IX, p. IfiO (158, sec. ed.). 1888. 



