FILARIA IMMITIS 



28 7 



that the filariae might possibly escape at the tip of the labium between 



the labellae. In a second and more recent paper 1 on the Transmission 



of F. immitis, Dr". Noe admits that it is impossible for the filariae to 



escape, as he had at first suggested. Having made numerous and 



suitable experiments he found that the filariae invariably died when 



extruded at the seat of the bend. He 



therefore believes that the filariae must 



leave their insect host, as suggested by 



Button, through the delicate structures 



between the labellae at the tip of the 



labium. 



Having noticed that the filariae (both 

 F. immitis and F. bancrofti) collect in 

 the lacunoma round the pharynx or 

 pumping organ of the mosquito, and 

 having found them also actually within 

 the pharynx, I suggested 2 that they 

 might pierce the delicate membrane 

 which connects the chitinous plates of 

 the pharynx, and thus reach the buccal 

 cavity of the insect, to pass between the 

 piercing organs into the definitive host. 

 I believe too much importance has been FlG 196 ._ The inferior end 

 given to the fact that the filariae are of the mouth organs of a mos- 



f ,! r i .,! ,, n ,. quito being introduced into the 



frequently found within the labium. ^ n of a d og> by which mea ns 



a filaria, lying between the 

 labium and the stylets, is 

 transmitted to the animal. 



Magnified. (After Noe.) 



Their presence in the labium does not 



. 



necessarily mean that they must escape 

 through that organ. It is obvious that 

 when a number of filariae have gathered 



round the pharynx, a few must be pushed forwards by new-comers 

 into those parts which continue the body cavity anteriorly. Con- 

 sequently the presence of filariae in the labium has no other signifi- 

 cance than their not uncommon presence within the palpi, from 

 which they can certainty find no means of escape. L. W. S.] 



Filaria recondita is another parasite of dogs, the larv;e of 

 which appear in the blood; fleas are their intermediary hosts. 



LITERATURE. 



BOWLBY. Two cases of Filaria immitis in Man. (The Lancet, 1889, i., p. 786.) 

 MAGELHAES, P. S. de. Die Filaria Bancrofti, Cobb., u. Filaria immitis, Leid. 



(C. f. B. u. P., 1892, xii., p. 511.) 

 GRASSI, B. Beitr. z. Kenntn. d. Entwickelungscyclus von 5 Paras, d.^ Hundes 



(Ibid., 1888, iv., p. 609.) 



'Noe, G., " Ulteriori studi sulla Filaria immitis" (Rend. Ace. d. Lincei, vol. xii., 

 1903). 



-Sambon, L. W,, " Fi!aria Bancrofti and Filaria immitis" (Lancet, 1902.) 



