436 A Contribution to the Zoblogy of Montana. [July, 
Rana halecina berlandievi—This abundant species replaces the 
preceding on the plains, and is the characteristic, and indeed the 
only Rana of the limited batrachian fauna of that widely extended 
district. On leaving the mountains this species immediately 
appears, accompanied by Phrynosoma douglassi, Crotalus confiu- 
entus, Heterodon simus, etc. The form which inhabits the plains 
differs in color and superior size from that found in the tide-water 
swamps of the Atlantic coast, on which account I have retained 
for it the sub-specific name at the head of the paragraph. 
Spea bombifrons Cope.—This species is characteristic of the 
northern parts of the Plains and Great Basin: It was éspecially 
common in the region north of the Missouri river and eastward 
of Fort Benton. Before my arrival there, rain had fallen, and the 
ruts of the wagon trails were filled with water. These ditches 
contained numerous examples of this species, together with 
Chorophilus triseriatus, Bufo dipternus and Amblystoma mavortium. 
heir metamorphosis was completed by that time (August 2oth), 
although some of the specimens were small. 
In Idaho, near latitude 43° 30’, is situated a body of water 
known as Market lake. Its extent is variable, for it is said to be ` 
dependent for its water supply on the_overflows of the Snake 
river, which is a few miles distant to the eastward. An old chan- 
nel leads from the river to the lake, giving probability to the 
statement. At the time of my passage through the region, the 
water was unusually high, for a portion of the stage road with 
parts of numerous telegraph poles, was submerged. The lake 
appeared to be about ten miles long by six in width. The country 
surrounding it is arid, and the sand which represents soil, rests 
on a basis of lava. The stage halted for a short time to enable me 
to examine the shore of the lake. -I found it to be lined witha. 
wind-row of grasshoppers (Caloptenus spretus) which had fallen 
into the water and been washed up, some living, others dead. 
Among them I found numerous large fat larve of Spea bombi- 
Jrons, occupying small spaces which they had cleared, quite out 
of the reach of the water. Their limbs were nearly fully grown, 
while their tails had suffered no absorption, and their jaws were 
toothless and cartilaginous ; some. quite larval in forta, others with 
wider gape. They were engaged in eating the grasshoppers, and 
I detected several specimens with the entire insects in their 
mouths. In some instances the grasshoppers’ bodies were too- 
