—. ——o - = er TS, 8 tS Sg a per 
78 * Journal of Entomology and Zoology 
HYMENOPTERA 
The Yellow and Black Mud-dauber, Sceliphron servillii Le- 
peletier.-This interesting dauber is common along all of the streams 
in the vicinity of Laguna Beach. The elongated mud cells about 
one inch long are built singly or placed side by side in series of 
from two to four and the whole covered with a continuous layer 
of mud completely obliterating the outlines of the individual cells. 
The cells were commonly placed on the undersides of large rocks 
or boulders in the near vicinity of the fresh water streams and 
often at the mouths of the canyons near the ocean. The nests 
were stored chiefly with yellow and brownish-gray crab spiders. 
In the cells and attacking the larvae of the mud-daubers was 
often found the maggot of a tachina fly, which proved to be 
Pachyaphthalmus floridensis Townsend,. The adults of this most 
interesting fly escaped from the masonry cells by the expansion 
and retraction of an inflatable bladder-like organ in the front of 
the head (ptilinum’?) which was used to moisten the mud and then 
scrape it away. Adults confined in glass vials were easily observed 
to continually endeavor to work their way through in this manner. 
Not all of the flies appeared to possess or to use such an organ, but 
whether or not this is a sexual characteristic was not determined. 
The fire ant, Solenopsis geminata Fab., was perhaps the com- 
monest ant in the vicinity of the laboratory. During July the 
ants were swarming from their ground nests in great numbers. 
The workers are small, entirely reddish or with small rounded black 
abdomens, the winged females are reddish throughout while the 
winged males are black. 
° Determined by J. M. Aldrich. 
