ON THE DEVELOPMENT OF DERMATOBIA HOMINIS. 489 



Dermatobia, to include this species, which thus became Dermatobia noxialis (Goudot). 

 In the face of the eminently satisfactory description of Say, however, it does not 

 appear that any reason yet offered can justify the introduction ha preference to Say's 

 name of Dermatobia noxialis (Goudot 1845) or of the slightly earlier form Derma- 

 tobia cyaniventris (Macquart 1843) which Blanchard has shown to be equivalent to 

 it. This form must be called Dermatobia hominis (Say 1822), or if the non-existence 

 of any conflicting form is established it may carry as authority (Gmelin 1788). 



IV. DESCRIPTIONS OF THE LARV.E. 



i. Larva A. The smallest larva, that one, namely, which was obtained from 

 the flesh of the toucan, measures 9.9 millimetres in length by 1.8 millimetres in breadth 

 at its widest part, about at the fifth somite. It is evidently in a state of nearly maxi- 

 mum extension and the furrows between adjacent somites show only as broad shallow 

 depressions (PI. XXXV, Figs. 1-3). 



Each of the anterior somites from the first to the fourth inclusive bears a band 

 of small hooks on its anterior margin. This band is separated from that of the next 

 succeeding somite by a smooth hookless area. The hooks are smallest on the first 

 somite and increase so as to become largest on the fourth. The band also is narrowest 

 on the first somite and widest on the third and fourth, where it exceeds in width the 

 clear area mentioned. On the fourth somite a semicircle of large hooks, interrupted 

 on the ventral surface, introduces an alternate series of complete and incomplete 

 circles of such hooks, of which there are three each. The fifth and sixth somites each 

 carry an anterior complete and a posterior incomplete circle, while the seventh somite 

 has the former but lacks the latter. In this specimen the incomplete row of large hooks 

 on the posterior region of a somite is separated by a maximum distance from the 

 anterior complete row of the succeeding somite, so that in dorsal view all the rows 

 appear almost equally spaced (PI. XXXV, Fig. 1). 



One may distinguish readily from this anterior region which bears the hooks 

 a smooth almost unsegmented region which is destitute of those structures except 

 on the terminal portion. There is a small decrease in diameter just behind the last 

 row of hooks, but the entire body tapers nearly uniformly from the fifth somite to the 

 posterior end. In the alcoholic specimen the body has a light brownish-yellow color 

 and the brown-black hooks stand out sharply as conspicuous objects on the surface, 

 even the smallest appearing as distinct dots under a hand lens. The hooks on the 

 terminal somites are much lighter in color, being dark reddish brown, and are less 



