DISEASES TRANSMITTED BY MOSQUITOES 261 



rossii. Fish swallowing the mosquito larvae take up the worm, which 

 continues its development toward maturity. The final host is not 

 known. 



Nemathelminthes: Nematoda: Filariidae^ 



AcantJwcheilonema perstans (Manson 1891), the cause of a form of 

 human FILARIASIS in Africa, is probably carried by biting flies. 

 Hodges in Uganda obtained an incomplete cycle in Mansonioides africanus 

 Theobald (Panoplite), Aedes argenteus (calopus) , A. sugens Wiedemann, 

 Anopheles costalis Loew, and a Culex, and negative results with a long 

 series of mosquitoes (Dye, 1905). Low (1903) obtained incomplete de- 

 velopment in Taeniorhynchus fuscopennatus. 



Dirofilaria immitis (Leidy, 1856), cause of CANINE FILARIASIS, 

 has been proven by Noe, Dye (1908), Grassi, and Fiilleborn (1912) to 

 pass its intermediate stages in the following mosquitoes — Anopheles 

 maculipennis Meigen (cloviger Fabricius), A. algeriensis Theobald, A. 

 bifurcafus Linnaeus, A. sinensis Wiedemann (pseudopictus Grassi), A. 

 superpictus Grassi, Culex quinquefasciatus Say (fatigans Wiedemann), 

 C. malarice Grassi, C. penicillaris Rondani, and Aedes vexans Meigen 

 (Cidex) exceptionally in C. pipiens, and with difficulty in Aedes argenteus 

 (^Stegomyia calopus). The microfilaria or embryo worms are taken up 

 by the mosquito with the blood of the dog. They soon pass from the 

 stomach into the Malpighian tubules. In ten days their development is 

 complete and they migrate towards the head and into the proboscis. 

 When an infected mosquito containing filariae in its proboscis feeds on a 

 dog, the worms escape by boring through a delicate membrane which 

 unites the labellEe, and thus get on the surface of the skin. If this is suf- 

 ficiently moist they penetrate the epidermis and may be found in the sub- 

 cutaneous tissues, whence they work toward the heart and great vessels 

 of the dog and there develop into adults. 



Dirofilaria repens Raillict and Henry (1911), cause of SUB- 

 CUTANEOUS CANINE FILIARIASIS, passes its intermediate stages 

 in the mosquito Aedes argenteus, its development having been demon- 

 strated by Bernard and Bauche (1913). Its life history is quite similar 

 to that of D. immitis. 



Filaria bancrofti Cobbold (1877), the cause of HUMAN FILARIA- 

 SIS or ELEPHANTIASIS, passes its intermediate stages in the mos- 

 quitoes. Complete development has been demonstrated in Anopheles rossi 

 Giles in India by James; A. costalis Loew in West Africa by Annett, 

 Dutton, and Elliot ; Culex pipiens in China by Manson ; C. quinquefascia- 

 tus Say (fatigans Wiedemann, ciliaris Bancroft, nigrithorax skusei Giles) 

 in China by Manson, in South Carolina by Francis, in Australia by Ban- 

 * For further discussion of the following worms see Chapter V. 



