FILARIA SANGUINIS HOMINIS IN THE MOSQUITO. 387 



showing out well. Mouth open, four-lipped, with signs of papillae on skin (fig. .37). In some 

 no trace of tail, in others a large beautifully transparent sickle into which the body dipped a 

 stumpy papilla. Rectum very evident. Granules in some escaping. A little, but very little, 

 movement in some heads. No trace discoverable of organs of generation. 



Fig. 31. From the thorax of a mosquito 156^ hours after capture. The ova had been deposited. In 

 this insect Filarice were found at almost all stages of development, from large " sausages " to 

 almost the Filaria of the sixth stage. One of the latter measured §■$" x yooo", and had three 

 distinct papillae on the tail. In this instance motion was most active in the tail, but the head 

 also was animated ; a prolapsus of intestine took place about the middle of the body. In 

 another, about ^V' long, the alimentary canal was very distinct, but rapidly became granular; 

 hernia occurred in two places, and the tail and head retreated from their integuments ; in the 

 case of the head it left unoccupied about yoVo" °f the integument, and in this the involution to 

 line the pharynx was very distinct. In some specimens the transparent sickle-shaped tail still 

 remained. 



Figs. 32, 33. The former is somewhat diagrammatic ; the latter was constructed from observation of two 

 full-grown Filarice at the sixth stage. The following are my notes of examination of the par- 

 ticular insects in which the originals were found : — 



(a) A large brown mosquito, 158i hours after capture, with ova still undeposited. Many 

 Filarice were found in the thorax, in the fifth stage, measuring from g 1 ,/' to £$", or thereabouts. 

 One Filaria had attained a more advanced stage ; it measured -^" x ^Vs"- It possessed great 

 activity, for it was in incessant motion, wriggling, coiling, and uncoiling. One movement was 

 peculiar ; it slowly, slightly approximated one end of the body to the other, and then suddenly 

 extended itself. The motion was too quick for the eye to follow. The viscera were very 

 difficult to make out. There were papillae at one end of the body, the other end was tapered, 

 and then abruptly rounded off. No trace of organs of generation visible. No trace of alimen- 

 tary canal, or anus, could be made out, all details being obscured either by extreme opacity or 

 extreme transparency of the body. Unlike Filarice at an earlier stage, this individual seemed 

 quite at home in the water ; the longer it remained in it the more active it became, and there 

 was no bulging of the body or escape of contents. The other Filarice found in this mosquito, 

 after moving languidly for a time, gradually became less active, and finally passive. Their 

 bodies at one or two places would bulge and then rupture, intestine protruding. In these 

 Filarice details of structure were easily made out. The large Filaria was visible to the 

 naked eye. 



(b) A large brown inosquito, 159i hours after capture, eggs still undeposited. The thorax 

 contained about 8 Filarice, " sausages " for the most part at an advanced stage. One measured 

 ^y ; another measured ^" x %i 3 ". The fore part of the body of this specimen was in con- 

 stant, active, swaying motion ; and the posterior half of the body apparently in the advanced 

 fifth stage, i. e. it looked more cellular, was affected by endosmosis, and possessed little motion. 

 The fore part had a firm, fibrous look, and the alimentary canal could sometimes be seen moving 

 inside the muscular and fibrous walls, accommodating itself to every movement. The mouth 

 was firmly pursed up, and the outline of the lips was quite indistinguishable. As it turned at 

 times towards the eye, the very centre seemed as if pointed to a spine, a ring of four or more 

 little spines, or papillae, surrounding it ; this is to some extent imagination, the perpetual move- 

 ment preventing reliable observation. On the extremity of the tail were two, perhaps three, 

 large, rounded papillae ; close to these, about two diameters of the body in advance, the anus 

 and rectum could be distinctly made out. A hernia of the intestine occurred after this animal 

 had been under observation about an hour. The hernia consisted entirely of intestine, no trace 

 of uterine tubes or testicle. The movement of the head end continued for an hour and a half, 



SECOND SERIES. — ZOOLOGY, VOL. II. 57 



