TRAGARDH: NOTES ON THE EARLIER STAGES OF ORCHESTES FAGI L. 75 
are no deeper than in the 1$t instar, and the segments on 
lateral view only slightly arched. 
The locomotorial bristles on the abdominal segments 
I—VII persist, but beside these the cuticle has become clo- 
thed with small spinulæ, especially at the sides of the body, 
subventrally. The head capsule is not more capable of being 
retracted in the prothorax than in the 1$t instar, and there 
are no plates on the prothorax. 
These changes take place in the 3'd instar (Fig. 3). This 
attains a length af 2,8 mm. Comparing it with the 24 instar, 
we notice the following differences. The intersegmental con- 
strictions, especially between the abdominal segments I—VII, 
have become much deeper, as in the last instar (comp TRA- 
GARDH |. c. Pl. I fig. 12); the cuticle is clothed with mi- 
nute, pointed spinulæ, arranged in transverse rows and point- 
ing backwards. On the ventral side the whole cuticle is 
clothed with them, except the prothorax, but on the dorsal 
side the prothorax, as well as the posterior half of the meso- 
and metathorax is naked, and at the top of the abdominal seg- 
ments I—VII there are narrow, elliptical, naked areas, which 
are of equal size in segments I—III, but decrease in size 
backwards, so that the 7th one is only twice as wide as it 
is long. The lateral locomotorial bristles of instar I and II 
have disappeared. 
Further differences are that the plates on the prothorax 
are developed, on the ventral side in the shape typical in 
the last instar, on the dorsal side narrower. 
The 34 instar thus perfectly resembles the full-grown 
larva, except for its smaller size, of course, and during its 
further growth the only noticeable change is the 4th instar 
having increased considerably more in width than in 
length. 
Comparison with O. populi. 
If we compare the changes which take place during the 
growth of the larva with those of ©. populz, the conformity 
of them in several respects is evident. 
The cuticle in both is quite smooth in the 1% instar 
