228 University of California Publications in Zoology [Vol. 27 
about the margin of Thornhill pond during the spring months when 
spawning was in progress. These are presumably ‘yearlings.’ They 
seem to take no part in the breeding activities. The sexually active 
animals measure from 30 millimeters upward in total length and 
they are believed to be two years or more in age. 
The span of life in Hyla regilla is unknown ; the largest individuals, 
over 40 millimeters in length, seem to constitute a size-group above the 
average of the breeding animals and may therefore represent a class 
three years (or even more) in age. These large individuals occur 
sparingly in the general population in various parts of the range 
although more are at hand from high mountain localities than from 
the lowlands. Specimens measuring more than 40 millimeters in 
head-and-body length are in the collection of the Museum of Verte- 
brate Zoology from the following localities : Oregon, 2 miles south of 
Barnes, and at Prineville, Crook County ; Nevada, Pine Forest Moun- 
tains, Humboldt County; California, Warren Peak, Warner Moun- 
tains, Modoc County; Porcupine Flat, 8100 feet, and Merced Grove 
Big Trees, 5400 feet, Yosemite National Park; Allendale, 200 feet, 
Alameda County; Panamint Mountains, Inyo County; Sierra Madre, 
1000 feet, Los Angeles County ; and Reehe Canon, 1000 feet, River- 
side County. 
Food. — Needham (1924, p. 3) examined and reported upon the 
stomach contents of 18 specimens of Rana [= Hyla] regilla collected 
in ponds at the head of Laguna Canon, Orange County, on August 24, 
1922. He states : 
To determine what was the food of these tree-frogs, on the 24th of August 
eighteen specimens were gathered by hand from the tules. Three of these had 
eaten nothing. The remaining fifteen had eaten a great variety of minute, mostly 
non-aquatic insects. About 80% of the food consisted about equally of small 
leaf -hoppers (Jassidae) and small Diptera. The leaf -hoppers were such as abound 
in shore vegetation. The Diptera were midges, small crane flies and a variety of 
small Muscoid flies many of which had doubtless developed as larvae in the waters 
of the pond. The remainder of the food consisted of Myrmecine ants (perhaps 
10%), a few parasitic Hymenoptera of the families Ichneumonidae and Bracon- 
idae, a few very small beetles, a number of spiders of the genus Erigone and a 
related genus, and a single terrestrial Isopod crustacean. The insects were all very 
small, the largest being an Ortalid fly, Anacampta latiuscula. 
The life-history in relation to the environment. — Hyla regilla 
enjoys a wide dispersal on the Pacific Coast latitudinally and alti- 
tudinally. Some members of the species live in the heat of the Mohave 
Desert, while others live in the glacial environment along the crest of 
the Sierra Nevada, and many stations of intermediate character are 
