1914] A Study of Dryophanta Erinacet. i: 
vessels, since the galls are produced before the eggs are hatched. 
Finally, he brings no evidence from a broad, comparative study 
of the Malpighian vessels of various gall-producing species 
to support his conclusion. 
The condition found in the bud-gall from which the sexual 
form of Dryophanta erinacei emerges is as follows: The egg 
rests on the living portion of the scale. When the larva emerges 
a viscous mass is adhering to it, but outside of this is a clear 
fluid resembling the secretion of the Malpighian vessels both in 
color and in action on glass when exposed to the air. The 
young galls soon appear enclosing the larva. In this instance 
the secretion of the Malpighian vessels appears to provide the 
first stimulus to gall-formation. With the agamic form, where 
the egg is enclosed in the plant tissue, one cannot observe the 
process so easily. 
On examining the galls of both the agamic and sexual forms 
of Dryophanta erinacei, it was noticed that the cavities were 
lined with growing tissue, abundantly supplied with chlorophyll, 
also that where the larva of Dryophanta erinacei rested, both 
it and the plant tissue were bathed at times with a colorless 
fluid. When the larva was placed on a glass slide it at once 
poured forth an abundance of this fluid, which always became 
opaque, milky white, on drying. By varying the position of 
the larva when placing it on a glass slide, this secretion was 
seen to pour forth from the anal region, while the head and thor- 
ax remained dry. About this time a study of sections of the 
larva revealed two tubules consisting of four cells each, which 
showed great activity. Longitudinal sections proved these to 
be cells of the Malpighian vessels, (Fig. 45, Pl. VI.). 
The Malpighian vessels of the agamic form of Dryophanta 
erinacei consist of two long tubules containing fifty-six rounded 
cells, with large nuclei, and attached to the hind gut, just at its 
point of union with the mid-intestine, (Fig. 48, Pl. VI.). They 
are whitish in color, the cells varying in size according to the 
larval period. They reach their maximum in the fourth larval 
stage. These larval tubules do not give rise to the adult 
vessels, but, degenerating in the prepupal and pupal stages, 
give place to the adult tubules which arise as evaginations of 
the hind-intestine, just below the attachment of the larval 
vessels. They are the largest glands in the body, extending 
slightly ventrad along the mid-intestine, their cephalic ends 
