1925] 
Storer: A Synopsis of the Amphibia of California 
251 
relatively heavy sediments. Any accumulations of mud which might 
occur in the creek beds would then be likely to be washed out, and 
any frogs in them would have their places of hibernation destroyed. 
Frogs which live in regions experiencing a prolonged low winter 
temperature hibernate to avoid being frozen and also because at that 
season the forms of insect and invertebrate life upon which they 
depend for food are scarce or entirely unavailable. Conditions in the 
California foothill country are quite different: There is little or no 
danger to the frogs from freezing, and some insects are active during 
the winter season. 
Specimens of Bana boylii boylii have been captured or seen abroad 
at several lowland stations on the dates given below, which suggests 
that if there is any period of inactivity it must be extremely short. 
The fact that few collectors have been at work in the midwinter period 
is a factor which must be considered in this connection. 
Extreme Seasonal Dates of Capture for Bana boylii boylii in California 
Locality 
Date of capture 
Authority 
Sweetwater Creek (3,800 feet), Mariposa 
Co 
Nov. 1, 1915 
Nov. 12, 1923 
M. V. Z. no. 5961 
Canon, near Monticello, Napa Co 
Storer, MS. 
Claremont Canon, near Berkeley, Ala- 
meda Co 
Nov. 17, 1912 
M. V. Z. nos. 4393—94 
Fairfax, Marin Co 
Feb. 2, 1913 
M. V. Z. nos. 4734-38 
Putah Canon, 4 mi. w. of Winters, Yolo 
Co 
Feb. 3, 1924 
Mar. 5, 1910 
Storer, MS. 
Muir Woods, Marin Co 
M. V. Z. no. 2408 
San Pablo Creek near Orinda, Contra 
Costa Co 
Mar. 14, 1922 
Storer, MS. 
Corral Hollow, sw. of Tracy, San Joaquin 
Co 
Mar. 14, 1911 
M. V. Z. no. 2566 
However these frogs may spend the ‘ winter’ period, it is obvious, 
from field experience, that the adults are active for several weeks 
before the advent of the breeding period. In the vicinity of San 
Francisco Bay the spawning season extends from the latter part of 
March to the first of May. No data are at hand for the season in the 
Sierra Nevada. In the heart of the Transition Zone of the north coast 
counties, for example in the' redwood belt of Mendocino County, the 
season is later. The exact time of spawning there is unknown, but 
late in June, 1922, I was unable to find either eggs or larvae. 
The table following gives data on the spawning of boylii in central 
California. The localities mentioned are mostly in the Upper Sonoran 
