10 Annals Entomological Society of America  [Vol. VII, 
Synergus erinacei: The larva of Synergus erinacei, (Fig. 38, Pl. IV) 
—summer brood—is fleshy, 1mm. in length, and possesses tridentate 
mandibles, the second tooth of which is pointed like an arrow-head. 
The setz are very small, difficult to locate, and without distinct tuber- 
clesat the base. Their location, (Fig. 44, Pl. V), is fourteen on the head, 
fourteen on the prothorax, twelve on the mesothorax, six on the meta- 
thorax, four on each of the eight following abdominal segments, six on 
the ninth, and eight on the tenth segment. 
The egg is white, the body being kidney-shaped, 240u.x80u., and is 
provided with a long neck 440u., Fig. 39, Pl. IV, shows one of these. 
The larva of Synergus erinacei (spring brood) is dark, fleshy, 700. 
long, (Fig. 40, Pl. IV). The mandibles are tridentate, the central tooth 
blunt. The sete are minute, without distinct tubercles, and distrib- 
uted as in Fig. 36, Pl. IV, eight on the head, sixteen on the prothorax, 
ten on each of the meso- and metathorax, eight on each of the first three 
abdominal segments, and six on each of the remaining segments. 
The eggs, two of which are shown in Fig. 41, Pl. IV, are white. The 
body is kidney-shaped 125yu.x56u., and provided with a neck 410u. 
in length. 
Parasites, their relation to Dryophanta erinacei, and to one 
another during the development of the gall. 
The Chalcids, Decatoma flava, Eurytoma studiosa, and 
Eurytoma auriceps were observed ovipositing from June tenth 
to the fourteenth. The method in all cases was similar, but the 
time occupied during oviposition, and the number of eggs 
deposited differed. 
Decatoma flava selected a spot on the midrib where Dryo- 
phanta erinacei had oviposited, thrust the long ovipositor down 
alongside the same channel, and deposited an egg in contact 
with that of the Cynipid. The ovipositor was then withdrawn, 
and the opening sealed. This required three minutes. 
Eurytoma studiosa and Eurytoma auriceps each selected a 
spot about the region where Dryophanta erinacei had ovipos- 
ited, and forcing the ovipositor into the fibro-vascular bundles 
placed from one to six eggs near, but not in contact, with the 
egg of the Cynipid. The eggs are usually laid in clusters, and 
appear black in the tissue of the leaf. The opening is sealed 
on the withdrawal of the ovipositor. The time consumed by 
these two species in oviposition was four minutes each. 
When the larva of Dryophanta 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 
