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MISC. PUBLICATION 631, U. S. DEPT. OF AGRICULTURE 



pairs of presutural acrosticals. The lateral abdominal spots are rounded and 

 well defined ; the median spots on the first three segments each reach the base of 

 the respective segment, thereby forming a connected band ; the fourth segment 

 has three small spots at the apex. Larva : The spinous areas are much as in 

 Wohlfahrtia vigil; the spines, however, are coarser. The anterior spiracle has 

 five or six papillae. 



Geographical Distribution. — Palaearctic Region : Spain, France, Italy, Ger- 

 many, Poland, Hungary, Yugoslavia, Bulgaria, European Russia (central and 

 southern), Morocco, Algeria, Libia, Egypt, Palestine, Iraq, Iran, Asiatic Russia, 

 south of Perm, Manchuria, Mongolia, China. Portchinsky states that this species 

 is absent from England, Netherlands, Finland, Denmark, Scandinavia, and 

 northern Russia. Ethiopian Region : Natal. 



Biology and Pathogenesis. — This species is a scourge in the steppes 

 of southeastern European and southern Asiatic Russia, in Asia Minor, 

 and in North Africa, where people lead a nomadic life which exposes 



them to the attacks of the parasite. 

 The adult flies rarely enter houses, 

 but frequent fields, orchards, and 

 other open places. The females are 

 flower feeders until they become 

 sexually mature. They like warmth 

 and light, and so do not fly in the 

 early morning or late evening, or in 

 dark, gloomy w T eather. 



The female will larviposit in 

 sores, cuts, w T ounds, and body open- 

 ings, the nose, eyes, and ears being 

 the most frequently attacked. Each 

 female, according to Portchinsky, 

 carries 124 to 168 larvae; in one 

 case of ophthalmomyiasis in Spain 

 70 larvae, which were submitted 

 for identification, w r ere said to rep- 

 resent about half the number taken 

 from one eye. The larvae burrow 

 into the tissue and grow rapidly; 

 they molt on the second or third day ; after another 3 or 4 days they 

 have completed the third larval stage and are ready to crawl out of 

 the wound to pupate. 



The larvae are extremely hardy. Specimens kept in 95-percent al- 

 cohol for an hour have been known to pupate and emerge as adults. 

 Larvae can survive for considerable lengths of time in pure hydro- 

 chloric acid, turpentine, or solutions of corrosive sublimate, boric acid, 

 or carbolic acid; however, they perish in sulfuric ether or in chloro- 

 form water (0.2 in 100). 



In areas infested by this fly it is dangerous to sleep out of doors 

 between 10 a. m. and 4 p. m. in the summer months. Because of the 

 large size, rapid growth, and often considerable numbers of the larvae, 

 the damage they do is often great unless the disease is treated at once. 

 In cases of auditory myiasis the larvae within the auditory meatus 

 usually penetrate the walls, and sometimes enter the cartilage. Deaf- 

 ness may result either from damage to the meatus or from the blocking 

 of it as a result of inflammatory growths. Destruction of tissue in the 

 nasal regions is often severe and has been known to cause death in 

 human beings. Myiasis in the eyeball may result in the complete 



Figure 10. — Wohlfahrtia magnified, 

 adult female. 



