ENTOMOLOGY

RELATION OF INSECTS TO THE PARASITIC WORMS 73cavity and this is probably the stage in which the parasite is transferredto the bird; whether as a result of ingestion of the louse by theswift, or as a result of the active migration of the worm from thelouse while the insect is engaged in biting, has not been determined.Filaria martis Gmelin, 1790Filaria mart'is (or Filaria quadrispina) according to various writersoccurs in its adult stage beneath the .skin and in the abdominal andthoracic cavities of Mustela foina. Baldasseroni (1909) has found filariaembryos in the intestine of ticks 'Ixodes ricinus) taken from a martenharboring the adult nematode, and he suggests that ticks may act asintermediate hosts. As in the case of Acanthocheilonema grassu, furtherevidence is n~cessary before ticks can be considered to playa part in thelife history of Filaria martis.Dirofilaria immitis (Leidy, 1856) Railliet and Henry, 1911This nematode, sometimes erroneously listed as a parasite of man",lives in the right side of the heart and pulmonary artery of the dog.The larvae are found in the circulation, most numerous at night as inthe case of Filaria bancrofti. As would be expected from the locationof the adult parasite it may give rise to serious symptoms, and affecteddogs commonly succumb to the disturbances which it causes. It is atroublesome parasite among hunting dogs in the Southern United States.:Soc (1900) showed that the larvae of this nematode continue their developmentin certain species of mosquitoes when sucked up with theblood of infested dogs. In 24 to 36 hours after reaching the stomachof the mosquito the larvae pass into the Malpighian tubules. Theyundergo a certain growth and development in this location, and 11 or 12days after reaching the mosquito they break out of the tubules, enter'the body cavity, and migrate to the labium. From the labium of tnemosquito they reach their final host, the dog, in the same manner asF. bancrofti reaches its human host, namely, by breaking through thinportions of the cuticle of the labium at the time the mosquito is engagedin biting its victim and then penetrate the skin, finally migrating to theheart. Mosquitoes infested with the larvll! of D. immitis are commonlykilled by the parasites owing to their destructive action on the l\Ialpighiantubules, Noc having observed that only about half the mosquitoes thatbecome infested survive. In Italy the common intermediate hosts appearto be Anopheles maculipennis, A. bifurcatus, A. (Myzorhyncht£s) sinensispseudopictus, and A. (Myzomyia) superpict1.b8 among anophelines; culicines,according to Noc such as Culex penicillaris, C. malariae, and exceptionallyC. pipiens, can also act as interm!!diate hosts.