12 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
The yellow-fill trout is largely on the gravels and about tbe north or sunny side 
of the lake. It is not often taken in deep water. 
It spawns ill spring, and the suckers devour the spawn in the streams and spawn- 
ing beds. The trout, however, feeds freely on young suckers, and sometimes on young 
trout. 
This species has the lower fins bright yellow ; there is a broad yellowish lateral 
shade, by which the species can be recognized in the water. The black spots are 
numerous and very small. There is little red under the throat and none at all else- 
where. The flesh is paler and more watery than that of the green back trout, which 
is usually regarded as the better food-fish. This paleness of color may be associated 
with its feeding habits, the trout which feed on Crustacea having the redder flesh.* 
5. Salmo niykiss stomias (Cope). Green-back Trout. (Plate I, Fig. 2.) 
This trout is very common in all the upper tributaries of the Arkansas Elver 
and in the Twin Lakes. From the common trout of the upper Missouri region it 
seems to differ somewhat, being of a greener color, with less red, and with redder 
flesh, all matters of very slight importance from the point of view of the systematist. 
The black spots are larger than in any other of our trout. The mouth is rather small 
and the scales are smaller than usual among these trout. 
These facts seem to indicate a distinction from the ordinarj^ Salmo myldns sufficient 
to justify the recognition of a subspecies, although the differences are small, and some 
of them may be inconstant. The trout taken by us in tributaries of the Platte seems 
to be identical with the “green back trout” of the Arkansas. The name Salmo 
stomias was given by Cope to specimens at first stated by him to have come from the 
“Platte Eiver, at Fort Eiley.” Later he stated that these came “not from the Platte, 
but from the Kansas, a very different river.” Fort Eiley is a town on the Kansas 
Eiver, east of the center of the State of Kansas. The Kansas Eiver rises in the sage 
plains of Eastern Colorado. It contains no trout anywhere. In fact, there are probably 
no waters in which trout can live within 500 miles of Fort Eiley. It is safe to presume 
that the types of Salmo stomias did not come from Fort Eiley. It is probable that 
* Since this report was sent to the printer, I have received from Mr. George R. Fisher, of Leadville, 
a very fine specimen of the yellow-fin trout. Mr. Fisher writes under date of June 2, 1890 : 
“I returned to Leadville in the spring and was here when the yellow-fins gathered at the mouth 
of the creeks immediately after the ice left the lakes waiting for the first rise in the streams. They 
appeared in schools at first but as the water raised they paired off, and went to the spawning beds in 
pairs. 
‘‘Before they mated they would take a trolling spoon or fly, and I believe grubs or minnow bait, 
but after pairing (they were nearly ready to spawn then) they would take nothing, and could only be 
taken with a grab-hook or spear. The largest yellow-fin taken this spring of which I know personally 
weighed 8 pounds 11^ ounces, and I believe that was the heaviest taken. This fish had been dressed 
before I knew of its capture or I would have sent it to you. 
“I got one from two fishermen named Tyler and McDonald which weighed something over 7 
pounds when first taken from the water, though I can’t give the exact weight. This fish I have put in 
alcohol sealed up in a tin box and sent to you by express. 
“It was kept on ice four days before putting in the alcohol and weighed at that time 6 pounds 14 
ounces. 
“ This weight was carefully made and I know was correct. 
“ I have kept the fish here just one week since it was put in the alcohol and I see it has lost a good 
deal of the yellow color on the fins and throat.” 
