FISHES OF COLORADO IO9 



bars of dark brown or blackish brown, each of which is more or less connected 

 with one of the dorsal blotches and covers portions of 5 to 7 rows of scales; 

 the space between the dorsal blotches and lateral line bars forming an irregular, 

 somewhat interrupted longitudinal stripe, lighter than the adjacent bars and 

 blotches; spaces between the bars crossing the lateral line light chocolate brown 

 in color; sides of the body below the lateral line markings yellowish or greenish, 

 sometimes with a well-defined stripe of burnt orange extending from the origin of 

 the pectorals to the anal fin; ventral parts yellowish white; top of the head dark 

 to almost black, sides of the head much mottled with black and brown; a very 

 distinct wedge-shaped bar of black or dark brown extending from the middle of 

 the ventral margin of the orbit to the ventral margin of the side of the head; 

 mouth and sides of the premaxillaries light yellow to whitish; fins hyaline, often 

 dusky, the rays crossed by several series of dark-brown dots which give the fins 

 as a whole a barred appearance, these bars most distinct on the caudal which is 

 crossed by 6 or 7 rows, quite distinct on the soft dorsal which has 4 to 6 rows, and 

 usually very faint on the other fins; males in breeding colors with all the markings 

 just described quite prominent and in addition the membranous portion of the 

 spinous dorsal between the rays is colored lilac or purple in the basal half of the 

 fin and vermilion in the outer half, the outer margin edged with bright blue, the 

 ventral parts also have more yellow or orange; size small; not exceeding two 

 inches and a half in length. 



The Iowa Darter has been taken in northern Illinois and as far north as Fort 

 Qu'Appelle, Canada. The Colorado records are the most westerly for Etheostoma 

 iowae. This darter is a species of the cold rapid streams and lakes of the north- 

 western portion of the Mississippi drainage. It seems to be one of the most hardy 

 species of the group, since it has been taken farther north and west than any other 

 darter and at the same time as far south as Arkansas. 



The stomach contents of six specimens from Longmont, October 17, 1903, 

 showed the food of this species to be of the same type as that of other species of 

 the genus.' The data are given below: 



45 mm., caddis-fly larvae, 100 per cent. 



47 mm., " " " , so per cent; Chironomid larvae, 25 per cent. Not full. 

 47 mm., " " " , 50 per cent; small annelids, 25 per cent; gastropods, 25 per cent. 

 50 mm., Chironomid larvae, 100 per cent. 



50 mm., " " , 50 per cent; small gastropods, 3° per cent. 



50 mm., " " , 75 per cent; small annelids, 10 per cent; a few Entomostraca; 



one small gastropod. 



A specimen of this darter taken from West Plum Creek near Castle Rock, 

 June 8, 1912, was in breeding colors. 



Colorado specimens. — University Museum: St. Vrain Creek, Longmont, October 17, 1903 

 (6 specimens, 45-55 mm.,), C. Juday and D. W. Spangler, No. 29; West Plum Creek near Castle 

 Rock, June 8, 1912 (2 specimens, 35-45 mm.), A. G. Vestal and M. M. Ellis, No. 407. 



" See Forbes and Richardson, Ichthyology of Illinois, p. 279, 1909. 



