THE FLIES THAT CAUSE MYIASIS IN MAX 137 



Guatemala, Brazil (Sao Paulo), Peru. Chile, Argentina. Patagonia. Palaearctic 

 Region : Ireland, Scotland. England. Spain. France, Netherlands, Italy, Corsica, 

 Norway. Sweden. Finland. Lapland (Swedish). Denmark. Germany, Poland, 

 Czechoslovakia. Austria. Hungary, Yugoslavia. Rumania, European Turkey, 

 Russia (widespread i. Azerbaijan. North Caucasus. Azores. Canary Islands, 

 Madeira. Morocco. Algeria. Tunisia. Libia, Egypt. Syria. Palestine. Siberia 

 (Tomsk, Kamchatka), China. Manchuria, Chosen, Japan. Oriental Region: Tai- 

 wan. India. Ethiopian Region: Tanganyika. Kenya, Southern Rhodesia. South 

 Africa (Transvaal). Australian Region: South Australia. Queensland. New 

 South Wales. Canberra. New Zealand. New Hebrides (Espiritu Santo Island ). 



Biology and Pathogenesis. — The females frequently enter houses 

 and may oviposit on foods, particularly those that are slightly tainted ; 

 it is probably in this way that man occasionally becomes parasitized. 

 Each female may produce 140 to 2<»<) eggs, which she scatters over the 

 food substratum. The first larval stage is of very brief duration, the 

 second somewhat longer, and the third, in which the carnivorous habit 

 becomes the most highly developed, is by far the longest. The length 

 of the larval life is from 15 to 25 days: higher temperatures and an 

 abundance of animal food will make it tend toward the lower figure. 

 Several generations may be produced in a summer. Normally, hiber- 

 nation takes place in the pupal stage, although larvae produced late in 

 the season, if they survive, may remain dormant over the winter. A 

 similar period of semidormancy may explain some of the protracted 

 cases of intestinal parasitism in man. 



A number of cases of human intestinal myiasis have been recorded. 

 One of these, described by Portchinsky {11-5). lasted from November 

 to the following March, all the time causing great pain, sickness, and 

 vomiting. The ill effects, which have been described ( Portchinsky) as 

 similar to "false typhus." may be due to the tearing of the mucous 

 lining of the intestine by the mouth hooks, with the resulting loss of 

 blood and entrance of toxic products into the wounds. 



Carter and Blacklock (24) described a case of cutaneous myiasis, 

 involving the mouth and nasal region, as well as a body wound, in a 

 monkey dying of acute tuberculosis, and Seguy has demonstrated the 

 experimental production of myiasis in wounds in rabbits, guinea pigs, 

 and hedgehogs. Nestling birds may be parasitized by this species, with 

 fatal results. 



Literature. — Important papers on the biology, larval structure, life 

 history, and role in myiasis are Portchinsky ( 115) . Keilin (66. p. 415) , 

 and Seguy (13^). 



MUSCINA ASSIMILIS (Fallen) 



Geographical Distribution. — Nearctic Region : Alaska. Newfoundland. New 

 Brunswick, Quebec. Manitoba, Alberta. Britisb Columbia. Maine. New Hamp- 

 shire. Massachusetts. Rhode Island. Connecticut, New York. New Jersey. Mary- 

 land. District of Columbia, Virginia, North Carolina. Tennessee. Ohio, Indiana. 

 Illinois. Minnesota, Wisconsin. Iowa, Missouri. North Dakota. South Dakota. 

 Montana. Idaho. Colorado, Utah. Nevada. New Mexico. Oregon, California. 

 Neotropical Region: Mexico. Palaearctic Region: England. Portugal. Spain. 

 France. Netherlands. Italy. Corsica, Norway. Sweden. Finland. Lapland (Swed- 

 ish). Denmark. Germany. Austria. Rumania. Russia (north to Arkhangelsk). 

 North Caucasus. Azores, Canary Islands. Palestine. Siberia (Kamchatka). Japan. 



Pathogenesis. — This species is known to produce at times a fatal 

 myiasis in nestling birds. Adults do not usually enter houses: there- 

 fore, the contact necessary for causing myiasis in man is probably 

 absent. 



Literature. — Keilin (06). Seguy (134). 



