ENTOMOLOGY

'74 SANITARY ENTOMOLOGYDirofilaria repens, Railliet Ilnd Henry, 1911In the adult stage this nematode, which is a very similar parasite toD. immitis, occurs in the subcutaneous connective tissue of the dog. Itslarvae enter the blood stream whence they are liable to be ingested byblood-sucking insects. According to Bernard and Bauche (1913) theyellow fever mosquito Aedes argenteua (Stegomyia calopus) acts as theintermediate host. These investigators while admitting that other speciesof mosquitoes might act as intermediate hosts of D. repens, found thatA. argmtcus best fulfilled the natural conditions for the transmissionof the parasite, and their experiments were carried out with this speciesof mosquito. They followed the various stages in the development ofthe larval nematodes in mosquitoes fed experimentally upon infested dogs.About 2 days after the mosquito has been fed the nematode larvae leavethe lumen of the alimentary tract and penetrate into the Malpighiantubules where they undergo mos~ of their growth and development. Bythe eighth day the larvae may be found in some cases to have migratedinto the body cavity and thoracic muscles and the last stage of developmentin mosquitoes may be found in the proboscis as early as the ninthday. Six young dogs (10 days old) were submitted to the bites ofA. argmteua (fed 10 to 15 days previously on infected dogs) every morningfor fifteen days. Six young dogs of the same age were kept as controls,not exposed to mosquito bites. The bitten dogs all died withinthirty days. Ecchymotic spots were found beneath the skin at the pointsof the mosquito bites, but no filarias were discovered. The other dogs allsurvived the experiment. Under natural conditions the youngest dogsfound infested with D. repms by Bernard and Bauche were at least 0.year old, hence the writers conclude that the development of the parasiteis very slow. Although they did not succeed in completing their experimentsby recovering the adult stage of the parasite in dogs, followingbites by infected mosquitoes, it appears safe to conclude that D. repensis transmitted by mosquitoes in a manner similar to that in which D.immitis is transmitted.Acanthocheilonema perstOlns (Manson, 1891) Railliet, Henry andLangeron, 1912This parasite occurs in man in tropical Africa and British Guiana,the adults in the intraperitoneal connective tissue and fatty tissue of theabdominal viscera and pericardium, and the first-stage larvae in theblood stream. The larvae exhibit no periodicity in their appearance inthe circulation, the name perstans having reference to this fact.Christy (1903) has suggested that Ornithodoros moubata may act as