On the Fishes of the Genus Arges. 'r2D 



by the much longer autcnnse, red tarsi, &c. From M. utjUis 

 it is known by the black hair on scutellum, red tarsi, &c. ; 

 from M. floris by the longer antennae, wings not yellowish, 

 &c. ; from M. montuna by the much smaller size, abdomen 

 less covered with hair, &c. 



Hab. Mesilla, New Mexico, at flowers of Parosela scoparia, 

 July 25 {Cockerell). 



University of Colorado, 

 Boulder, Colorado, U.S.A., 

 March 10, 1905. 



LXIX. — The Systematic Arrangement of the Fishes of the 

 Genus Argcs. By C. Tate Regax, B.A. 



In my monograph * of the Loricariidse I included nineteen 

 species in the genus Arges. INIessrs Evermann and Kendall f, 

 Avho have received some fishes of this genus from Ecuador, 

 have written a short paper in Avliich they consider the 

 chai acters which I have used for the distinction and arransre- 

 ment of the species as of very little value. 



With regard to the structure of the adipose fin, Messrs. 

 Evermann and Kendall, describing the specimens they have 

 received, write : " When first received these examples revealed 

 no trace of an adipose fin excepting what was soon discovered 

 to be a short spine, sometimes naked but in most cases con- 

 cealed under the skin, evidenced only by a slight elevation, 

 which was at first regarded as a 'short adipose fin'; but 

 in alcohol there gradually appeared on the back a low, thick, 

 fleshy fold which increased in resemblance to a thick adipose 

 fin with their continuance in the preservative, and, in the 

 smaller individuals, became thin and very much like an 

 adipose fin in appearance." They proceed to quote Stein- 

 dachner''s descriptions of the adipose fin in Arges sabalo, 

 A. longifilis, A. prenadilla, and A. peruanus, and they then 

 state : " These descriptions show conclusively that what has 

 been so regarded is not a true adipose fin, which conclusion 

 our specimens substantiate. It is evident that the presence 

 of the supposed adipose tin on the diflerent species is simply 

 due to the action of the preservative and that there is no 

 true adipose ; and the smaller the individual and the longer 



* Trans. Zool. Soc. xvii. pt. iii. pp. 191 324, pis. ix.-xxi. (1901). 

 t Proc. Biol. Soc. AVashington, xviii. pp. 9i-10G (1905). 



