INJURIOUS INSECTS OF I909 AND IQIO. 131 
A Jumping Seed-gall on Oak Trees. 
Mr. C. N. Ruedlinger, Forester of the Minneapolis Parks, 
brought in on July 3d, 1909, some leaves of bur-oak, which bore 
on their undersides large numbers of little round galls. These galls 
contained the larvae of small insect, apparently Cynipid or Chalcid, 
and a rustling sound could be heard across an ordinary-sized room 
because of the movement of the larvae inside the galls. Mr. Rued- 
linger also brought a large number of the galls which he had col- 
lected from the ground, these having become detached from the 
leaves of the trees and fallen down in large numbers. In their de- 
tached condition the insects had the power of making the galls 
which surrounded them hop several inches from one place to an- 
other. When on the trees, there occurred from a few to several hun- 
dred of these galls on a single leaf. They seldom were found to- 
ward the basal portions of the blade of the leaf, but were scattered 
over the rest of the leaf. These “jumping seeds” as the public called 
them, excited much interest. 
Corresponding with the positions of the galls on the lower side 
of the leaves, there were convexities on the upper surface. These 
galls, while round, were flattened somewhat, that is, depressed. 
Some of the galls were opened at the time they were brought 
in, and the insects inside were found to be in the pupal stage. When 
the galls reached the stage at which they detached themselves from 
the leaves they were a very light chrome yellow color, and about 2 
mm. in diameter. These were placed in lamp-chimneys, the ends of 
which were covered with muslin, and were placed on the ground 
both inside and outside of the insectary. In this way they could 
be kept and given the natural moisture of the earth. The galls con- 
tinued to show their hopping movements with considerable vigor 
as late as August 4th, and a slight hopping was noticeable as late 
as August 21st. 
A large number of insects, mostly Chalcids, emerged in these 
experiments from July Ist to August 2d. These were apparently 
parasites on the real gall-formers, as but a small percentage of 
the galls show that insects had emerged trom them, and the hop- 
ping continued for a considerable number of days after these in- 
sects ceased to emerge. 
These parasites were all mounted in balsam on slides, and some 
of the leaves bearing the galls were pressed and put up in Riker 
Mounts, and a large number of the galls were bottled in alcohol 
and formalin. 
