174 ■ NEW YORK STATE MUSEUM 



were horned dace of about the same size, and 3 were unidentifiable. 

 The 25 bullheads had eaten at least 26 other fishes, all of practically 

 the same size. 



Seven fisli had eaten large dragon lly nymphs, of which 6 be- 

 longed to the family Aeschnidae, and 2 had eaten Libellulidae. 

 One fish only had eaten a May fly nymph and 3 had eaten small 

 crawfish less than 2 inches in length. Three had eaten small fila- 

 mentous algae (Spirogyra, Zygnema and Cyanophyceae) and only 

 4 had eaten any appreciable quantity of silt. 



Food constituents individually considered. By far the most 

 important single element of bullhead food at this time and place 

 was small sunfishes. These abounded everywhere among the sub- 

 merged aquatic plants growing on muddy bottoms. They were 

 taken by small boys in minnow traps and by ourselves when col- 

 lecting with sieve nets. There must be fearful decimation in num- 

 bers of young sunfishes in submerged pastures infested by bull- 

 heads. Horned dace are also very common about the borders of 

 these same water-weed patches and are likewise raken in minnow 

 traps and seines. 



Although the bullheads lie on the bottom, the dragon fly nymphs 

 eaten did not show them to be bottom feeders. The nymphs of 

 the Aeschnidae habitually climb about over the stems of water 

 weeds and are rarely found on the bottom. They are protectively 

 colored and are hardly noticeable when at rest, but swim away 

 with a jerky gait produced by successive ejections of the water 

 from the gill chamber ; and when once dislodged and set going 

 they are no doubt captured easily by the bullheads. The nymphs 

 of the Libellulidae are typical bottom sprawlers. Only two of these 

 were eaten, however. They lie concealed amid the bottom silt and 

 it is only when they are brushed out of place that they kick actively 

 "and are easily found. The single May fly represented, of course, 

 a very insignificant part of the total food taken, but neither is it a 

 bottom form. While not clearly identifiable it was certainly one 

 of the climbing nymphs of the Baetinae. Crawfish diet was proven 

 by the presence of two small nipper feet. These, indeed, are 

 typical bottom forms; and their habit of jumping backwards when 

 disturbed and evading their enemies in a cloud of sediment, or 

 fleeing into hiding under a stone, is, of course, well known to every 

 cue. Small quantities of algae and of silt were eaten; so small, in 

 fact, that they might very well have been taken quite accidentally 

 in the quest for other food, and there is no evidence whatever 



