386 DR. P. MANSON ON THE METAMORPHOSIS OF 



seen, i.e. soon after the body of the insect was immersed and broken np in water, part of the 

 alimentary canal was visible as a distinct tube, and the body was for the most part veiy clear. 

 After a time the alimentary canal became obscured by the cellules becoming granular and con- 

 fused. Granular matter escaped from the anus. The cellules were smaller than those in 

 figs. 21, 22, & 23. Several parasites were crushed under the cover-glass ; in these chitinous 

 integument was readily seen. Measurement y' s " x ■g^g". 

 Fig. 25. From the thorax of a mosquito found dead on the morning of the seventh day after capture. 

 The arrangement of cells round the alimentary canal, and on the inside of integument, very 

 easily made out. The cells were plump and nucleated. In addition to the peripheral layer of 

 cells the walls of the body appeared to be strengthened by a sort of thick corium, to the inside 

 of which the cells were attached. There was a distinct space, a sort of peritoneal cavity, 

 between the cortical and intestinal cells. In one specimen the head moved slowly at intervals. 

 Mouth in all pursed up. 



Kg. 26. From thorax. Mosquito found dead 144 hours after capture, seen alive 8 hours before. Fight 

 such Fi/ariee found. Two of them had slight movement; the largest measured -g^-" Xyj 5 "; 

 another ^ 5 " x y] 5 . The sickle-shaped tail was purely integumental, very faint and fine. The 

 body in some projected into this as a papilla ; in others it was abruptly truncated. Iu most 

 the anus was a large bag with well-defined wall, and from it granules escaped. Alimentary 

 canal traced as a tube two thirds down the body, but union with rectum not distinctly discerned. 

 Mouth widely open. Cellular structure of body obscure. Many shining granules in the wall 

 of the alimentary canal. 



Fig. 27. From thorax of mosquito found dead and adhering to damp side of bottle, 132 hours after 

 capture. Altogether there were about six Fi/ariee in the insect's thorax, and all in an advanced 

 state of development ; mouth, anus, alimentary canal, distinct ; body cellulo-granular. Mouth 

 in every case pursed up so that the lips were with difficulty defined. The specimen represented 

 was more advanced than the others. The anterior part of body had thinned down and 

 lengthened, while the posterior part remained full size, giving the animal the hock-bottle 

 appearance. The cephalic end very transparent, alimentary tube in it barely visible. Mouth 

 pursed up, and no lips discernible. Cephalic end exhibited slow swaying movement when fresh. 

 Measurements ^"xjo'jo" anteriorly, and 5J-5" posteriorly. 



Fig. 28. From mosquito 135 hours after capture. Many advanced Filarice found in this insect. Some 

 of them showed thinning and commencing extension of cephalic end. The specimen repre- 

 sented had grown at both extremities, particularly at the cephalic ; but a portion of the middle 

 of the animal had not yet become extended, hence its peculiar appearance. The entire animal 

 measured ^" in length ; the neck was xoV>o"> tue posterior part gl ", and the bulging centre 

 - 1 ,," in diameter. Lips distinct ; body cellulo-granular; tail, a long delicate sickle. Some 

 motion exhibited. 



Fig. 29. From a mosquito 144 hours after capture. Many advanced Filarice in thorax, some of them 

 undergoing stretching. One measured t^" x ^ s " ; another j} () x j\ t) ". Oesophagus could be 

 made out as a thick-walled tube in most ; in some it terminated in a bulbous valvular-looking 

 arrangement, from which sprang the intestine. Mouth distinctly lipped ; a pharynx seen in 

 some. In some no tail could be detected, in others a very transparent sickle was seen. Body 

 cellulo-granular ; no movements. 



Fig. 30. From mosquito 152 hours after capture. About 15 large Filarice were found in the thorax. 

 The largest is represented, it measured ^q" by ^\ 5 " posteriorly, 7^/' anteriorly. A number 

 were found crowded together in one corner of the slide at various stages of extension from the 

 T J " up to the r-y in length. Cellular structure of the body in some most apparent. Oeso- 

 phagus in some particularly distinct, the single layer of nucleated cells constituting the wall 



