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Indiana University Studies 
including longitudinal sections, reproduces photographs of the 
pupae and a small photograph of the agamic female ovipositing 
in a bud, includes drawings of the eggs with figures of the eggs 
in position on the bud scales, gives details of wings, some of 
the mouthparts and antennal segments, including the sensory 
pits of the terminal segments of the antennae (structures 
which may serve the insect in finding its host and the buds 
suitable for oviposition) , details of larval chaetotaxy, and 
histologic sections of the larvae showing especially the Mal- 
pigian tubules and oenocytes. 
There are nine species of parasitic hymenoptera recorded 
from these galls. Triggerson found these “primarily parasitic 
on . . . erinacei, and secondarily on each other.” Two- 
thirds of the nearly one thousand parasites that author bred 
were determined as Decatoma flava (Ashmead). The para- 
sites were observed ovipositing about the middle of June (June 
10 to 14) , Decatoma flava selecting a spot on the mid-rib where 
the gall maker had oviposited, thrusting its ovipositor down 
alongside the same channel, depositing a single egg in contact 
with that of the cynipid, and finally sealing the opening thru 
which the egg had been placed. The two species of Eurytoma 
oviposited in the fibro-vascular bundles of the leaf, near but 
not in contact with the egg of the cynipid, the eggs of these 
parasites being layed in clusters of up to six. 
Quoting again from Triggerson : “When the larva of Dryo- 
phanta erinacei emerges from the egg, it proceeds at once to 
form a cavity which encloses the eggs surrounding it. In 
newly-forming galls the cavity is small, and the egg of the 
parasites is frequently found resting in the abdominal angle 
of the larva of Dryophanta erinacei. Here it often hatches. 
The larva breaks the shell near the base of the neck . . .and 
emerges, proceeding to attack the host in the abdominal region. 
If the Cynipid larva has just molted it is destroyed at once. 
If on the other hand, it escapes the attacks of the parasites 
during this period, they will live together until the next molt 
occurs, when the host is almost invariably killed and eaten. 
Only on rare occasions have the host and parasite been found 
living together in the same cavity until both have reached 
1 mm. in length. 
“If two parasitic larvae of the same or different species are 
found in one cavity in the early stages, the stronger alone 
