THE FLIES THAT CAUSE MYIASIS IX MAX 161 



strong longitudinal veins (r\ and r 8 ) r s sometimes being forked, and 

 four or five weaker ones extending from them to or toward the pos- 

 terior margin ; the strong veins are near the costa and usually do not 

 extend beyond the basal half of the wing. 



The Genus MEGASELIA Rondani 



The name Aphiochaeta is sometimes used, either in a generic or sub- 

 generic sense, for some members of this genus. 



The following characters will apply to most members of this genus, 

 including both of those treated here : The head is of the usual phorid 

 type, with a short proboscis ; the epistoma is not produced ; there are 

 two pairs of bristles on the anterior part of the front, above the anten- 

 nae, both of these pairs being proclinate. The wings are well devel- 

 oped and normal, the vein r s being forked. The posterior tibia bears 

 a row of dense, contiguous hairs on its dorsal surface and a row of 

 short, well spaced bristles on the posterodorsal surface. 



Larva. — The larva (fig. 98) may be recognized by its small size (the 

 mature larvae of the species treated here being about 1 mm. in length) , 

 the broad, somewhat flattened body segments, and the method of pro- 

 gression which resembles that of a geometrid or measuring worm. 

 The puparium is somewhat shorter and more robust than the larva ; 

 the anterior spiracles are extended into long rodlike processes, which 

 may be simple or. on the other hand, rather complex in structure. 



Literature. — Patton (103) has described the stages and life his- 

 tories of the two species known to be involved in myiasis of man and 

 animals. 



Taxonomy. — The genus is a large one, and exact identifications can 

 be made only by a specialist who has access to the necessary literature 

 and collections. Consequently, no recognition characters that will do 

 more than separate the species treated here can be given in this work. 



MEGASELIA SCALARIS (Loew) 



(Fig. 97) 



Synonyms. — Aphiochaeta xanthina Speiser; Aphiochaeta ferruginca Brunetti. 



Recognition Characters. — Adult : The thorax is yellow or yellowish brown, 

 with the halteres and legs clear yellow; the abdomen is yellowish brown, some- 

 times light but often darker, usually banded with brown, sometimes almost wholly 

 brown in the male. Length, 2-3 mm. Larva : Color, dirty white. The head has 

 a pair of toothed mandibles in place of the usual hooks. Each body segment is 

 provided with short fleshy processes on the dorsal and lateral surfaces : these 

 processes gradually increase in length to the eighth segment, but the longest 

 are shorter than the humps bearing the posterior spiracles ; the processes are 

 not hairy. 



Geographical Distribution. — Nearctic Region : New York. New Jersey, Penn- 

 sylvania, Maryland, District of Columbia, Georgia, Florida. Indiana, South 

 Dakota, Texas. Neotropical Region : Mexico. British Honduras. El Salvador, 

 Honduras, Canal Zone, Bermuda, Bahama Islands, Cuba. Jamaica. Dominican 

 Republic. Puerto Rico, Lesser Antilles *St. Vincent. Grenada, Tobago), Colombia. 

 Galapagos Islands, Brazil, Peru, Argentina. Palaearctic Region: Germany. 

 Canary Islands. Oriental Region : India, Burma, China. Ethiopian Region : 

 Senegal (Dakar), Sierra Leone, Gold Coast, Cameroun. Ethiopia. Belgian Congo. 

 Rodriquez. Australian Region: Guam, Samoa, Fiji, Hawaiian Islands. 



Biology and Pathogenesis. — Eggs are laid in various media, in- 

 cluding fruits, stale meat, excrement, and carrion. The females are 

 attracted to foul-smelling exudations from sores, and oviposition 



752113°— 48 11 



