THE FLIES THAT CAUSE MYIASIS IN MAN 91 



female is about one-third, that of the male about one-tenth, the width of the 

 head. The thorax is black, its dorsum with dense grayish pollen ; there are two 

 postsutural intra-alars; the scutellum bears at least four pairs of strong lateral 

 bristles. The abdomen is blue with silvery tesselation. Larva : The mature larva 

 is about 17 mm. in length and whitish to yellowish. Segments 2 to 9 have 

 complete anterior spinulose bands. The anterior spiracles end in 7 to 9 processes ; 

 the posterior spiracular plates are subcircular and are separated by approxi- 

 mately the diameter of one plate; the peritreme is broad and is completely 

 sclerotized ; its inner outline between the slits is distinctly scalloped. 



Geographical Distribution. — Widespread throughout the temperate parts 

 of the world. Nearctic Region : Greenland, Alaska, New Brunswick, Quebec, 

 Ontario, Alberta, British Columbia, Maine, New Hampshire, Vermont, Massa- 

 chusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Mary- 

 land, District of Columbia, Virginia, North Carolina, Georgia, Florida, Alabama, 

 Mississippi, Tennessee, Ohio, Indiana, Minnesota, Wisconsin, Iowa, Missouri, 

 South Dakota, Nebraska, Kansas, Arkansas, Louisiana, Oklahoma, Texas, Mon- 

 tana, Idaho, Colorado, Utah, Nevada, New Mexico, Arizona, Washington, Oregon, 

 California. Neotropical Region : Mexico (south to Mexico City), Chile, Argentina, 

 Patagonia, Tierra del Fuego, Falkland Islands. Palaearctic Region : Spitsbergen, 

 Iceland, Ireland, Scotland, England, Spain, France, Netherlands, Italy, Corsica, 

 Sardinia, Sicily, Malta, Norway, Sweden, Denmark, Germany, Poland, Czecho- 

 slovakia, Austria, Hungary, Rumania, Bulgaria, European Russia (north to 

 Arkhangelsk), Azerbaijan, Azores, Canary Islands, Madeira, Morocco, Tangier, 

 Tunisia, Libia, Egypt, Levant States, Dodecanese, Syria, Iraq, Iran, Commander 

 Island, China, Japan. Oriental Region: India (northern mountainous parts). 

 Ethiopian Region : Cape of Good Hope. Australian Region : South Australia, 

 New South Wales, Victoria, Tasmania, New Zealand. 



Biology and Pathogenesis. — Eggs are deposited on the breeding 

 medium, where they hatch in a day's time or less. A female may 

 deposit as many as 180 eggs at a time, though she usually deposits 

 fewer: she may produce from 540 to 720 eggs in her lifetime. The 

 larva grows rapidly ; under favorable conditions it is ready to pupate 

 in about a week after oviposition. It then leaves the breeding medium 

 and burrows into the soil, where pupation takes place, the pupal state, 

 in the summertime, lasting from a week to 10 days. With allowance 

 made for the preoviposition stage, a complete generation requires 30 

 to 40 days in summer. The adults occur commonly in houses during 

 the cooler seasons and may remain active until November in north 

 temperate latitudes. Hibernation probably occurs in the pupal stage. 

 The normal breeding medium is carrion; eggs may be deposited on 

 tainted meat. 



As a parasite on man it is uncommon, but may at times produce 

 severe myiasis. Entrance is obtained through diseased tissue. 

 Onorato (96) cites two cases in the rectal region secondary to ulcers, 

 one in the ear secondary to otitis, and one in the oral cavities secondary 

 to stomatitis. Other cases on record show a preexisting diseased con- 

 dition of the organ affected. The larvae may burrow deeply into 

 healthy tissues and may be present in numbers up to 100 or more. It 

 has been reported as a secondary sheep maggot of minor importance. 



This species has been accused of producing gastrointestinal myiasis, 

 live maggots having been reported on several occasions from stools 

 and vomitus under conditions which would seem to bar the possibility 

 of subsequent infestation. If such records are correct, the larvae or 

 eggs were probably introduced with tainted prepared meats. 



CALLIPHORA CROCEIPALPIS Jaennicke 



Recognition Characters. — Adult : The eyes are practically bare, those of the 

 male being very short pubescent; the front of the male is very narrow; the 

 cheeks are black-haired, the hairy parts also being black; the palpi and the 



