529 



ceeds in rearing them and identifying them with their respective 

 adults. 



Chironomus sp. A 



Pupa. — Length, 4-5 mm. Frontal tubercles small, thick. Abdom- 

 inal segments 2-6 with pale, short, and rather broad dorsal setulae, 

 which are not distinct on posterior portion of the segments; second 

 segment with the normal apical row of closely placed setulae, wdiich 

 are rather long and pale; eighth segment with a conspicuous bifid 

 apical lateral thorn (PI. XXXI, Fig. 11. a, b) which varies some- 

 times in structure; fringe of usual apical appendages fine, closely 

 I)laced, and of moderate length ; a pair of unfringed apical appendages 

 project caudad of the usual pair. 



Illinois localitv, Thompson's Lake, near Havana, April 2/, 19 14 

 (C. A. Hart and ']. R. Malloch). 



Pupal exuviae of this species were floating on the surface of 

 Thompson's Lake in numbers, but no example was found which con- 

 tained the imago, and though the latter is probably described in this 

 jiaper it is impossible to associate the two because of the very large 

 number of species occurring on the lake when the pupa w^as taken. 



Chironomus sp. B 



Larz'a. — Length, 15 mm. Red? Head broad and short; eye spots 

 small, widely separated, the space between the upper and lower spots 

 equal to nearly three times the height of the upper one ; labrum as in 

 Figure 7, Plate XXIII; antennae (PI. XXX, Fig. 6) situated on slight- 

 ly raised bases, basal joint more than four times as long as its diam- 

 eter, the remaining joints one third as long as basal, third joint slightly 

 less than a third as long as second, fourth subequal to third, fifth short- 

 er than fourth; maxillary palpus as in Figure 5 ; mandibles without dis- 

 tinct teeth (Fig. 3) ; labial teeth truncate (PI. XXIX, Fig. 5). Elev- 

 enth segment without ventral blood-gills ; anterior and posterior pseu- 

 dopods stout, the former with weak apical hairs, the latter with the 

 normal apical claws; dorsal tufts weak, consisting of about six hairs, 

 the basal papillae short and inconspicuous, dorsal blood-gills large, 

 about 2.5 times as long as their diameter. 



Illinois localities : Illinois River at Havana, Hardin, Grafton, and 

 Meredosia. Taken by dredging. 



No attempt was made to rear the species. 



Chiroxomus sp. C 



Larva. — Length, 6-7 mm. Greenish, with a slight reddish tinge. 

 Structurally this species closely resembles digitatits. The antennae of 



