224 
University of California Publications in Zoology [Vol. 27 
Locality 
Date 
Remarks 
2 mi. s. of Inverness, Marin Co 
Merced Lake, 7,600 feet, Yosemite 
National Park 
July 5, 1919 
July 17, 1921 
July 18, 1922 
Aug. 10, 1922 
A newly metamorphosed hyla 
Larvae up to 37 mm. in total 
length 
A few larvae and two recently 
metamorphosed hylas 
Large larvae and recently meta- 
morphosed hylas 
Lafayette 
San Pablo Hills, e. of El Cerrito, 
Contra Costa Co 
1 L. H. Miller, MS. 
2 C. L. Camp, MS. 
3 Dickerson, 1906, p. 137. 
Except as indicated the data given are from the author’s observations. 
Mr. Henry W. Henshaw found “vast numbers of the young, in 
all stages, from the tadpole to the fully developed Hyla ... in a 
stagnant pool upon Santa Cruz Island” in June, 1875 (Yarrow and 
Henshaw, 1878, p. 208). 
Hyla regilla deposits its eggs in almost any sort of quiet water 
(pi. 3, fig. 5). The shallow margins of permanent ponds and tempo- 
rary pools formed in depressions at the sides of roadways are the two 
most usual locations. Occasionally eggs are deposited at the side of 
a stream where there is little or no current. In water 75 millimeters 
or less in depth the egg clusters may be attached to leaves or sticks 
on the bottom ; in deeper water attachment may be made at depths 
down to 100 millimeters, but most of the masses are found floating on 
the water surface. The specific gravity of the egg mass is so nearly 
that of water that a very slight attachment is all that is required to 
keep the mass from sinking. 
The egg clusters of this hyla contain a varying number of eggs. 
In laboratory aquaria and occasionally in the field single eggs are 
laid. Some masses total over 60 eggs. Probably the number in a 
mass reflects in a general way the degree of solitude experienced by a 
pair when eggs are deposited. Where only one female is laying a few 
large clumps are to be found. Where many hylas have been spawning 
in one place the egg masses are small. 
At times very large numbers of eggs are laid in a relatively small 
area. In a small pool near the main Thornhill pond I found, on 
January 25, 1913, 59 masses in an area approximately 10 by 15 feet. 
Additional masses were laid in this same area on subsequent nights. 
