54 ILLINOIS BIOLOGICAL MONOGRAPHS [54 



the time the sand settles again, the head of the male is once more poking 

 out of the nest entrance. Food is entirely bottom fauna of small size, as 

 entomostraca, small Crustacea like Hyalella and Gammarus, and small 

 mayfly and damsel-fly nymphs. 



80. Boleosoma nigrum (Raf.). Johnny Darter. 



The characteristic and most abundant darter of the region, found in 

 every lake and in every river and stream. It is equally at home in the 

 swift current of the Bark river and the still waters of the large lakes, its 

 one demand being gravel bottom or coarse sand. Mud it strictly avoids. 

 It is distinctly a shallow water darter, found resting upon the bottom 

 supported by the pectoral fins in true darter attitude. It is not particularly 

 timid, often joining Notropis blennius in investigating one's toes when 

 one goes swimming. However, when frightened, Johnny is off amid a 

 swirl of sand and is found in a rigid, expectant attitude when the cloud 

 settles. The eggs are laid on clear sand, no nest being constructed that 

 is worthy of the name, during May and very early June. The food of the 

 species is composed of Chironomus and Simulium larvae to about 50%; 

 with Crustacea (Hyalella) and entomostraca (Cyclops, Daphnia, etc.) 

 composing the other half. 



81. Ammocrypta pellucida (Baird). Sand Darter. 



This peculiar darter is recorded from a single specimen taken by me 

 in the Ashippun river. The region from which it came is one of clear sand 

 over a stretch of perhaps 300 yards, with not a sign of aquatic vegetation 

 of any sort, or of a pebble larger than a sand grain. In looking over this 

 barren stretch I found this darter buried in the sand, with nothing visible 

 but the eyes and mouth. Such is the normal habit of the species: avoiding 

 vegetation they protect themselves by imbedding the body in the soft 

 sand. I know nothing about its breeding habits or its food, as careful 

 search here and in other similar localities has revealed no further specimens. 



82. Etheostoma iowae (Jordan & Meek). Iowa Darter. 



A common species in certain lakes, Oconomowoc, Pine, and La Belle, 

 where it inhabits the shore waters above a sand or fine gravel bottom with 

 some low, submerged vegetation present. Here it isassociatedwith-Bo/ecwwa 

 nigrum, Etheostoma coeruleum, and Notropis blennius. While the pectoral 

 fins are well developed, the species has rather less of the darter habit of 

 resting upon them, the fish being more constantly in motion than the 

 Johnny darter. While capable of very rapid motion, the Iowa darter tends 

 to be more deliberate than many other species of darters, though the fish 

 is, of course, a member of the bottom fauna. The food is largely copepods, 

 with some insect larvae and many small mayfly and stonefly nymphs. 

 I have taken gravid females during May and early June. 



