496 ON THE DEVELOPMENT OF DERMATOBIA HOMINIS. 



On the ventral side parallel rows of smaller scattered hooks accompany the com- 

 plete rows on the fifth and sixth somites, as also in the other specimens, and one finds 

 a few such hooks on the dorsal surface as well. There are no hooks posterior to the 

 complete row of the seventh somite save a single small hook immediately next the gap 

 on the mid-ventral line, although the figure given by Matas appears to show four 

 large hooks on the smooth constricted region. The large hooks measure 240 to 270 

 micra in length over all by 180 to 200 micra in diameter at the base. The smaller 

 hooks agree closely with the sizes given for those of the smallest larva of my series. 

 Finally, as regards the character of the terminal somites I find substantial agreement 

 with the description already given. 



One or two minor points need correction in the otherwise excellent description 

 given by Matas. As already noted, the size is incorrectly stated and the figure does 

 not represent the true form of the larva, since even the proportions of different regions, 

 the number of somites, and the number of large hooks are not accurately reproduced. 

 The first four somites are very clearly shown by the specimen, though incorrectly 

 numbered in the description, and the statement that "the stigmata are hidden within 

 the anal fissure" is also an error; they agree perfectly in position with those shown 

 in Figure 5 (PI. XXXV). Finally, the "Punctiform and blackish tuberosities on 

 the two [four] upper segments" are true hooks, as already described in detail. 



The other specimen obtained by Matas measures 2.5 millimetres in breadth at the 

 fifth somite by 6.3 millimetres in length, of which a little less than one-half (tt) falls 

 on the constricted posterior portion. From the transverse folding which this region 

 presents it is evidently contracted, and this is further evinced by the fact that the 

 terminal somite is almost entirely withdrawn within the preceding one. The hooks 

 are throughout of the same size and arrangement as in the specimens previously 

 described. The circles of large hooks are constituted as follows: 



Number of Somite. Character of Row. 



IV Incomplete 



V Complete 



Incomplete 7 



VI Complete 



Incomplete 



VII Complete 



In the first incomplete circle of large hooks the two median dorsals arenas in the 

 other specimens, somewhat smaller infsize and noticeably out of fine. Supplementary 

 parallel rows of small scattered hooks lie posterior to the complete circles on the fifth 

 and sixth somites and are most perfect on the ventral surface; the mid-ventral hook 



