38 ILLINOIS BIOLOGICAL MONOGRAPHS [38 



35. Notropis heterodon (Cope). Black-striped Minnow. 



Common locally in most of the larger lakes — Oconomowoc, La Belle, 

 Golden, Keesus, Pewaukee, Pine — where the species goes in schools 

 often numbering two hundred individuals. Seldom taken in streams, the 

 only record I have being the Oconomowoc river below the outlet of Ocono- 

 mowoc lake from which the fish may well have come. The Milwaukee 

 Museum has specimens from Stonebank creek at Hartland. The fish feed 

 almost entirely upon entomostraca, though I have found insect larvae and 

 Hyalella, very small snails (Physa) and leech cases (Placobdella parasitica) 

 in a number of instances. A hardy bait minnow, much used for silver 

 bass fishing. 



36. Notropis blennius (Girard). Straw-colored Minnow. 



Probably the most abundant minnow in all of the large, sand-and- 

 gravel lakes. In such lakes as Oconomowoc, La Belle, and Pine it is the 

 dominant shore minnow, present in incredible numbers. The species is 

 gregarious and I have seen schools in Oconomowoc lake containing at least 

 5,000. individuals. They are commonly associated with Fundulus diaphanus 

 menona and the young of Lepomis pallidus, L. cyanellus, Perca Jiavescens 

 and Ambloplites rupestris. Spawning occurs along the shores in water from 

 twelve to eighteen inches deep in late May and early June, usually under 

 the protection of shallow water submerged vegetation. The standard 

 small bait minnow of the region. I have found the fish in Oconomowoc 

 lake often infected with large tapeworms (Ligula sp.). In August, 1925, 

 I took a minnow 5 cms. long whose body cavity contained a Ligulid 6.2 

 cms. in length. 



37. Notropis hudsonius (DeWitt Clinton). Spot-tailed Minnow. 

 Exceedingly abundant in Bark, Ashippun and Oconomowoc rivers; less 



so in the Fox river and its tributaries. To some extent found in Oconomo- 

 woc lake; rare in Okauchee, Pine, La Belle, and North. In the rivers, 

 which seems to be its normal habitat, the species prefers clear water, 

 and gravel bottom with not much current. It is associated with Notropis 

 comutus, Hybopsis kentuckiensis, and Semotilus atromaculatus. A hardy 

 bait minnow, though very small in size, seldom reaching a length greater 

 than 3 inches. While Forbes and Richardson feel that the species inter- 

 grades with N. whipplii, I can see no evidence within the region to bear 

 out such a conclusion. To the extent of 80% the food is animal matter, 

 being entomostraca, small Crustacea, and occasionally young mollusca 

 of any species that may be at hand. 



38. Notropis whipplii (Girard). Silverfin Minnow; Lemon-fin Minnow. 

 The name used locally for these minnows depends on the season of the 



year and on the sex of the minnow in question. Extremely abundant in the 

 Muckwonago river, and quite common in places in the Oconomowoc and 

 Fox rivers. It is a swift water, clear gravel-bottom species, which avoids 



