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hooks, the upper extremity of which projects, and two long supporting 
rods which fureate basally, and on the tips of which the hooks articu- 
late. (Fig. 44 f, 9.) 
Second stage-—In the absence of any knowl- 
edge of an intermediate form, the larva found in 
the esophagus may be considered as the second 
stage (Fig. 48 «@). The individuals vary in length 
from 11 to 14 mm. and are quite smooth and de- 
void of prickles, except some minute ones, which 
appear like black specks partly surrounding the 
anal spiracles (Fig. 48 d) and a few extremely 
minute ones just above the mouth-parts (Fig. 48 
c). The former, or those around the anal spira- 
cles, are of peculiar structure, and consist of a 
circular, brownish-black, slightly elevated base, '-48:—HypoperMa LingaTA. 
x 3 c eed Second stage of larva from 
in the center of which arises a short, stout, pos-  ecophagus. a, larva; B, en- 
teriorly curved and very minute spine, less than largement of cephalic seg- 
one-half the diameter of the base in length. The ee pests ae 
mouth-parts are more prominent than in the first anal segment, showing spira- 
stage and the apical portion is broadened and “°* #7 Pines (original). 
furcate near the base (Fig. 49 b,c). This larva does not differ in any 
essential way from the stage first found under the skin in the back 
before the perforation to the surface is made. (See Fig. 49 a, b, c.) 
Fic. 49.—HYPODERMA LINEATA: a, second stage of larva from back; b and c, enlargement of ex- 
tremities; d, ventral view of third stage with details of extremities ate and f; g, dorsal view of ma- 
ture larva with enlargement of anal spiracles at h; i, ditto, lateral view—natural size indicated by side 
lines (original). f 
Third stage—In this stage, which is the second form of the larva 
found in the back (Fig. 49 d, e, f), the larva again diverges markedly 
from the second or preceding stage and acquires many of the charac- 
teristics of the mature larva. It tapers, however, considerably toward 
the posterior extremity rather than the reverse, and the spinous arma- 
ture varies considerably in different specimens, but ventrally is similar 
