Fig. 134.—Wing venation of Diptera. A, first posterior cell; B, discal mid cross-vein; a, auxiliary vein; C, marginal cell; D, submarginal cell. In the illustration of the Chrysops wing, the letter “B,” indicating the discal cell, is misplaced. It should be in the same relative position as in the Tabanus wing.
Tumbu Fly Disease
This African myiasis is due to the penetration of thighs or buttocks by the larvae of Cordylobia anthropophaga. The appearance of the tumefied area is quite similar to that of the tumor of Dermatobia cyaniventris and the treatment is similar.
Craw-craw
This is a rather chronic papular skin disease which is reported from the west coast of Africa. These papules may be as large as a small pea and are quite hard. They are found chiefly on legs and arms. The proximal lymphatic glands may be enlarged.
Fig. 135.—Markings of breathing slits on posterior stigmata of various larvae. 1. Musca domestica, showing both stigmata; 2. Calliphora vomitoria; 3. Stomoxys calcitrans; 4. Auchmeromyia luteola; 5. Cordylobia anthropophaga; 6. Sarcophaga magnifica.
Undoubtedly many of the cases called craw-craw are scabies. In fact the Africans give the name to a host of different skin affections. O’Niel thought he had found a filarial larva in one of his cases and Nielly incriminated a nematode larva of the Anguillulidae family. The cause is unknown and the disease very intractable to treatment.