904 The American Naturalist. [October, 
ENTOMOLOGY. 
Two Twig Galls on Populus Fremontei.—On the 25th of 
April, 1892, two galls were found on growing twigs of Populus fremon- 
tei in Las Cruces, New Mexico, and the following are descriptions of 
them. 
Warted Gall.—Length and breadth, 22 mm., thickness 13 mm. 
Formed on side of twig, round, roughly and irregularly circular in 
outline, rather flattened, excrescentic or finely warted on the whole 
upper surface and edges or sides, involving about one-half of the body 
of the twig, the under surface next the twig covered by the thin spread 
bark expanded from the involved surface of the twig. Excrescentic 
portion of gall overlapping the smoother inferior portion on edges, 
brownish gray in color, the lower surface covered by the spread bark 
being pale greenish gray like the bark of the twig. Gall woody 
interiorly, the excrescentic portion filled with small cavities. On twig 
5 to 6 mm. in diameter, but spread to 7 mm. at center of gall. 
One specimen. Occupants unknown. 
Tumor-like Gall.—Length, 12 mm.; width, about 53 mm. ; height 
(from twig), about 4 mm. Elongate, in shape something like a min- 
iature mud-wasp cell, growing lengthwise on twig like an elongate 
tumor, one side broadly amalgamated with body of twig. Externally 
rather smooth, being wholly covered by the distended bark of the 
twig. Pale greenish gray in color, like the adjoining bark. Gall 
maker emerges by a circular exit hole 1 mm. in diameter, situated at 
the tip end of the gall, which is the more pointed end without reference 
to its being distal or proximal on the twig. 
Three galls approximated on same twig, two being grown into each 
other side by side. A gall fly had escaped from each gall at some time 
previous to April 3, 1893. Two of the galls showed the exit hole con- 
spicuous and open, but the third appeared to be still tenanted. On 
examination, however, it was found that the fly had escaped from this 
one also, but the circular flap of bark, which either the larva cuts on 
all sides but one before assuming the pupa state or else the adult cuts 
before it can emerge from the pupal cell, leaving a hinge-like portion 
intact, had sprung back in place perfectly closing and concealing the 
place of exit. From the cast pupal skins which remained in the cells, 
the occupant is apparently hymenopterous. 
"Edited by Clarence M. Weed, New Hampshire College, Durham, N. H. 
