THE FLIES THAT CAUSE MYIASIS IN MAX 133 



Literature. — For a key to the species of the world and a discussion 

 of the biology see Seguy {136) ; for a discussion of the medical im- 

 portance see Zumpt (160). 



STOMOXYS CALCITRANS (Linnaeus) 



The Stablefly ; the Biting Housefly 



Recognition Characters. — Adult: This is a grayish to black fly, about 5 or 

 6 mm. in length ; the pollen of the thorax and abdomen is mainly gray, but there 

 are four vittae of brownish pollen on the thorax and spots of pollen of the same 

 color on the abdomen, those of the intermediate segments being in the form of 

 a single spot at the base and a pair at the apex of each segment. The legs are 

 black, with more or less yellow on the tibiae. The front tarsus of the male 

 lacks fine, erect hair on the anterior surface. Larva: Too little is known of 

 the larvae of this genus to enable one to give specific characters. 



Geographical Distribution. — Nearctic Region : Alaska. Nova Scotia, Quebec, 

 Ontario, Manitoba. Saskatchewan, Alberta. British Columbia, United States 

 (records from every state and the District of Columbia). Neotropical Region: 

 Mexico, Guatemala, Honduras, Costa Rica, Panama, Canal Zone, Bermuda. 

 Bahama Islands, Cuba, Jamaica, Haiti, Dominican Republic, Puerto Rico. 

 Antigua, St. Vincent, Barbados. Grenada. Trinidad. Colombia. Galapagos Islands, 

 Ecuador. Venezuela, British Guiana, Brazil. Peru. Bolivia. Chile. Argentina, Pata- 

 gonia. Palaearctic Region : Scotland, England, Portugal, Spain, France, Nether- 

 lands. Belgium, Switzerland. Italy. Corsica. Sardinia. Sicily. Norway. Sweden, 

 Finland, Lapland (Swedish), Denmark. Germany. Austria, Hungary. Yugoslavia, 

 Rumania, Greece. European Turkey. Russia I widespread I. Azores, Canary Is- 

 lands. Madeira, Morocco, Algeria. Libia. Egypt, Turkey (Asiatic), Dodecanese. 

 Palestine. Arabia, Iraq. Iran. Asiatic Russia (widespread I. China. Chosen. Japan. 

 Oriental Region : India. Ceylon, Burma, Thailand, Indo-China, Federated Malay 

 States. Taiwan, Philippine Islands, Sumatra, Java. Celebes. Ethiopian Region: 

 Gambia, Guinea, Sierra Leone, Ivory Coast, Gold Coast, Nigeria. Sudan. Eritrea, 

 Ethiopia, Belgian Congo, Angola, Uganda, Kenya. Tanganyika, Zanzibar. Nyasa- 

 land, Mozambique, Rhodesia, South Africa (Transvaal, Basutoland, Zululand. 

 Cape of Good Hope), Madagascar, Seychelles. Mauritius. Australian Region: 

 Australia (every state), Tasmania. New Zealand. New Caledonia. Guam, Samoa, 

 Fiji, Hawaiian Islands. 



Biology and Pathogenesis. — The eggs hatch in 1 to 3 days. The 

 larva completes its development in 11 to 30 days, depending on the food 

 and physical conditions of the environment : the pupal period, in the 

 summer, lasts 6 to 20 days. The rate of development is much slower 

 than that of the housefly. In cooler climates hibernation takes place 

 in the larval or pupal stage; in warmer climates there is no true hiber- 

 nation. 



Zumpt (160) briefly discusses the three recorded cases of myiasis sup- 

 posedly caused by this fly. and concludes that the records were probably 

 erroneous. However, the subject cannot be dismissed so lightly. In 

 the case reported by Porter (119, p. 377) an adult was reared from 

 larvae obtained from the neglected foot of a native stable boy in 

 South Africa: and Knipling and Rainwater (75) have recorded this 

 species from wounds in an unspecified domestic animal. As to hit est i- 

 nal myiasis. Onorato (96) describes a case in which maggots were ex- 

 pelled in the vomit of a boy in Tripolitania. in the presence of a 

 physician, and 25 of them were reared to the adult stage. It would 

 seem. then, that this specie- may, on rare occasions, produce both gas- 

 tric and traumatic myiasis. 



