5384 Philippine Journal of Science 1919 
extent—the galls occurring most abundantly within a belt ex- 
tending from sea level to an altitude of about 600 meters. Be- 
yond that limit the galls are either very scarce or entirely 
absent. It was further noted that from sea level to an altitude 
of about 600 meters the greatest number of species occurred 
nearer sea level, their abundance diminishing with each 100- 
meter zone upward. This fact may be ascribed to at least two 
causes; namely, the prevalence or scarcity of the plant hosts 
in a given altitudinal zone; and the influence of temperature, 
moisture, pressure, absence or presence of natural enemies, and 
possibly other factors on the distribution of gall-making insects 
in different altitudinal zones. The following is the distribu- 
tion of gall species, found by me, with respect to altitudes: 
Species. 
Sea level to 100 meters 36 
100 meters to 200 meters 31 
200 meters to 300 meters 25 
300 meters to 400 meters 23 
400 meters to 500 meters 15 
500 meters to 600 meters 9 
600 meters to 900 meters 1 
Above 900 meters 0 
In the following pages the galls are divided into groups, ac- 
cording to their causative agents, which are indicated by the 
center heads; and each species is treated separately, with the 
specific name of the plant host as a side heading. Accounts of 
the causal insects, including descriptions of new species, will 
be given in later publications. 
All of the specimen numbers cited in this paper refer to the 
collection of the department of entomology, College of Agri- 
culture, Los Bafios, Laguna, Philippine Islands. 
GALLS CAUSED BY ITONIDIDA (CECIDOMYIIDA) 
Acalypha stipulacea Klotz. Euphorbiacez. 
Leaf galls caused by Schizomyia acalyphe Felt. 
Monothalamous; subcylindrical; red; basally yellowish or 
‘concolorous with leaf; covered all over with long, stiff, bristle- 
like hairs. Walls thin, fleshy; interior smooth. Opening api- 
cal; covered with a circular flap with edges confluent with the 
rest of the gall’s surface, not visible until a few minutes pre- 
vious to emergence of midges. Pupal exuvie often found pro- 
jecting half way out of opening. 
Length of galls, 3.5 to 5.5 millimeters; diameter at base, 1.5 
to 2. 
