2 U. S. BUREAU OF FISHERIES. 



mentioned Arkansas, Kansas, and Illinois siinfishes as identical and 

 called the species L. hurmlh. Under this name the orange-spotted 

 simfish has been known to the present time. Boulenger (1895), in 

 his " Catalogue of fishes of the British Museum," mentions the fish 

 under the name Eupomotis hiimilk. 



ECOLOGY. 



Although Lepoinis huinilis has been described particularly as a 

 stream fish, it has come under our observation more especially as a 

 pondfish at the U. S. Fisheries Biological Station at Fairport, 

 Iowa, and as a common species in the quiet winding bayous of the 

 delta country of northern Louisiana, particularly in Walnut Bayou, 

 near Mound, in Madison Parish. The species in the Fairport ponds 

 was introduced into the reservoir of the station by direct pumpage 

 from the Mississippi River. Since its accidental introduction into 

 the artificial experimental pond sj'stem of the station it has flourished 

 and has become a persistent species even where it has been associated 

 wnth carnivorous fishes. In Louisiana it was captured re*^ularly in 

 monthly collections of fishes taken in connection with an investiga- 

 tion of the relation of fish to mosquito control.^ There it was com- 

 monly associated with GambuHia afjinh^ Pomoxis annularis^ Lepomh 

 pallidus, Ahra/mis clmjsolcucns^ Dorosoma cepedimium^ Atneiurus 

 nehulosus, and occasionally with Chcvnohryttus gulosus and Microp- 

 terus salmoides. It frequented the shallower Avater of the bayou 

 and was most abundant in the impounded sections of the stream from 

 Avhich all submerged, floating, or overhanging vegetation had been 

 removed and in the areas where clumps and thickets of willows broke 

 the surface but in which the water was seldom clear and contained 

 no submerged vegetation. 



In impounded sections of Walnut Bayou, Mound, La., the fre- 

 quency of the species was 14.* In the borrow pits outside the Mis- 

 sissippi River levees the frequency was 3.7. In " wild " and cleared 

 sections of Walnut Bayou the frecpiencies were 1.7 and 1.4, respec- 

 tively, while in Cypress Bayou (Barney and Anson, 1920), a near-by 

 stream characterized by heavy surface and submerged growths, re- 

 spectively, of Lemna, Spirodela, and Wolffia and Ccratophylluui, and 

 by colder w^ater, the frequency was 0.6. In a woodland lake, in 

 w^hich occasionally submerged algie obtained a temporary foothold 

 and where Lcpo7)iis cyanelhis, Ahranu'fi chryfiolpuGas^ and Aphredo- 

 denis sayamis were very munerous, the frequency was 1.1. The 

 species from our observations prefers a sluggish stream or pond in 

 which there is a scarcity of vegetation. Muddy or cloudy Avater, 

 although not necessarily a preference, is not disadvantageous to the 

 species. 



Forbes and Richardson (1908) have found the orange-spotted sun- 

 fish most frequently in Illinois in creeks (2.06 frequency),^ next in 

 small rivers (1.51), and then in lowland lakes (1.19), none at all 



s The authors were engaged as representatives of the U. S. Bureau of Fisheries, -which 

 had entered into cooperation with the U. S. Bureau of Entomology, and the observations 

 from Mound here recorded were made in the vicinity of the field laboratory of the latter 

 bureau. 



* Frequencies here mentioned were obtained by dividing the number of humilin caught 

 in baul» of a seine of certain mesh and length over given areas by the number of collec- 

 tions so made. 



5 Frequencies here mentioned are the ratios of frequency of occurrence. 



