696
FILARIASIS
[CHAP.
by the mosquito[1] (Fülleborn, Dirofilaria immitis; Bahr, Filaria bancrofti) (Fig. 105); they do not enter through the mosquito-made wound, as formerly conjectured, but near it. Apparently the filariæ in some instances can discriminate between flesh and vegetable, for in mosquitoes fed on bananas the parasites
Fig. 106.—Section of mosquito about sixteen days after it had fed on a filariated patient. The filaria has escaped from the thoracic muscles. (From a microphotograph by Mr. Spitta.)
had not been deceived into passing into so inhospitable a medium: up to forty days after the insect was
- ↑ Annett and Dutton pointed out that there is a weak point in the chitinous skeleton of the labium just where the labella are jointed on, and suggested that it is at this weak point the parasites escape. Bancroft confirmed this suggestion by showing that the filariæ enclosed within the labium will escape readily at this point under the least pressure. Noè also, in a more recent paper, agrees with Annett and Dutton and rejects his former hypothesis (held in common with Grassi) to the effect that the filariæ escape through a rupture in the contiguity of the labium when it is buckled up during haustellation. Noè satisfied himself by numerous experiments that the filariæ invariably die when extruded at the seat of the bend. Finally, Lebredo, by actual experiment, proved that the filariæ escape in this way. He placed living mosquitoes on slides, irrigated them with a weak saline
