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



eye or ear. Nasal cases, in particular, may terminate fatally for the 

 host. The genitals may be affected, although this species is not in- 

 volved in enteric or vesicular myiasis. 



In India infestation of the nose, mouth, and accessory sinuses is 

 known as peenash. A swollen face in an otherwise healthy individ- 

 ual, associated with headaches, fever, burning pains in the nasal region, 

 and a sero-sanguineous discharge from the nostrils, should suggest 

 myiasis. Man is apparently attacked with relatively more frequency 

 in India than in other parts of the range of this fly, whereas cattle 

 suffer from it more in Africa. However, a number of human cases 

 have been recorded from that continent. 



Status as a Parasite. — Chrysomya bezzhtna is a specific myiasis- 

 producing fly ; it cannot breed in carrion or excrement and is dependent 

 upon living tissue for its existence. 



Literature. — Patton (99, 102) has given considerable information 

 on the biology of this fly in India, with descriptions of 59 cases of 

 mviasis in man and 71 in animals. For accounts of the biology of 

 the fly in Africa, see Cuthbertson (31, 32) . 



CHRYSOMYA MEGACEPHALA (Fabricius) 



Synonyms. — Pycnoso»ia meyuccphala (Fabricius) ; Compsomyia megacephala 

 (Fabricius) : Chrysomyia dux (Escbscholtz). 



Recognition Characters. — Adult : The head is black above, except for the 

 frontalia, which are usually reddish ; the face and cheeks are orange ; the thorax 

 and abdomen are greenish blue with purple reflections, the first abdominal seg- 

 ment and the posterior margins of the second and third being black. The head 

 is unusually broad ; in the female the front is much broader than in related 

 species, and its sides, as well as those of the frontalia, distinctly bulge outward 

 in the middle (fig. 29) ; in the male the upper facets are distinctly larger than 

 the lower ones, the line of demarcation being sharp (fig. 31). The stigmatic 

 bristle is present ; the mesothoracic spiracle is brownish ; and the squamae 

 are dirty yellow to brown. Length, about 11 mm. Larva : The mature larva 

 is a smooth, whitish maggot similar to C. bezzhina but readily distinguishable 

 by the much weaker mouth hooks and body spines. The posterior spiracles have 

 a thinner peritreme and its gap at the button is broader ; the slits are longer ; 

 and there are no breaks in the membrane between the slits. The anterior 

 spiracles end in 10 to 13 fingerlike processes. 



Geographical Distribution. — Palaearctic Region: Egypt, Iran, China (north 

 to Peiping), Japan. Oriental Region: India, Ceylon, Chagos Islands, Thailand, 

 French Indo-China, Federated Malay States, Taiwan, Philippine Islands, Suma- 

 tra, Borneo, Java, Timor, Celebes. Ethiopian Region : Seychelles, Mauritius ; 

 other records from this region cannot be accepted without confirmation. Aus- 

 tralian Region: North Australia, Queensland, New South Wales, New Zealand, 

 New Hebrides (Espiritu Santo Island), Solomon Islands, Aru, Wokan, Misol, 

 Ternate Islands, Guam, Saipan, Samoa (Apia, Upolu, Savaii), Fiji, Tonga, 

 Hawaiian Islands. 



Biology and Pathogenesis. — This is a very common household and 

 bazaar pest in the Oriental Region and the Pacific islands, where the 

 adults are said to swarm over meats, sweets, and other foodstuffs. 

 The larvae breed in decomposing animal matter, but occasionally occur 

 in diseased animal tissue. A number of cases of myiasis of wounds, 

 body openings, and sinuses have been attributed to this species, al- 

 though most of them should probably be referred to O. bezziana. 

 Because of the confusion as to the identity of these two species, many 

 records in literature are erroneous. 



Chrysomya megacephala may breed in certain foodstuffs; further- 

 more, the larva has been shown to be able to endure oxygen deficiency 

 resulting from immersion in human urine for as many as 2 days. 



