318 



hooks, the upper extremity of which projects, and two long supporting 

 rods which furcate basally, and on tlic ti])s of which the hooks iirticu- 

 Lite. (Fig. 44/,//.) 



Second stage. — In the absence of any knowl- 

 edge of an intermediate form, the larva found in 

 thi' esophagus may be considered as the second 

 stage (Fig. 4:S a). The individuals vary in length 

 from 11 to 14 mm. and are (juite smooth and de- 

 void of prickles, except sonu' minute ones, which 

 appear like black specks juutly surrounding the 

 anal spiracles (Fig. 48 <I) 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, fi"'18.-Hypodermalineata. 



^, . f-i-i ■ ^ i^ij. ' Second stage of larva Jrom 



m the center of which arises a smu-t, stout, pos- 

 teriorly curved and very minute spine, less than 

 one-half the diameter of the base in length. The 

 mouth-parts are more ])rominent than in the first 

 stage and the apical portion is broadened and 

 furcate near the base (Fig. 49 b, e). This larva does not differ in any 

 essential way fi-om the stage first found under the skin in the back 

 before the perforation to the surface is made. (See Fig. 49 a, h, c.) 



esophagus, a, larva; 6, en- 

 largement of cephalic seg- 

 ments, end view; c, mouth- 

 l)arts ; rf, enlarged end view of 

 anal segment, showing spira- 

 cles and spines (original). 



Fig. 49.— Hypodeema 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 at e and/; </, dorsal view of ma- 

 ture larva with enlargement of anal spiracles at A; i. ditto, lateral view— naturaj size indicated hy side 

 lines (original). 



Third stage. — In this stage, which is the second form of the larva 

 found in the back (Fig. 49 d, e, /), 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 



