310 



axillary vein indistinct, perhaps sometimes absent. Alar squamae 

 small, nearly bare of fringe, but larger and with coarse fringe in 

 Mydas ; thoracic squamae absent. 



Life-history mainly unknown, except that the larvae are said to 

 live in decaying wood and to resemble those of the ASILID.E. 

 Williston states that the larva of a North American species 

 (Mydas fulvipes, Walsh) preys upon Coleopterous larvae, and notes 

 the pupa of M. clavatus, Drury. The perfect insects have been 

 accused of being predatory, but there seems to be little decisive 

 evidence on the matter. An Egyptian species is said to be 

 predatory on other insects, catching them in the air ; and another 

 species is recorded as parasitic on the larvae of Longicorn beetles 



The MTDAIDJB occur chiefly in the New World and Australia, 

 only about 15 species being Palaearctic and six Oriental, of 

 which four are Indian. 



Their peculiar venation differentiates them easily from all other 

 groups, except the NEMESTIUNIDJE and APIOCERID^E. These 

 latter are a small non- Oriental group that has been at various 

 times associated with the BOMBYLIIDJE, THEEEVID^, and ASILID^E. 

 There is some resemblance in the venation of the MYDAID^E to 

 that of the NEMESTIUNID.E, but the bodily structure and general 

 facies of the latter are different. 



The presence also in the NEMESTHIXIDJE of what has been 

 conveniently though incorrectly termed the "diagonal vein" will 

 also immediately separate that family from the present one. 



Verrall has carefully analysed the systematic position of the 

 present family (Brit. Flies, v, p. 605), and in the same volume 

 (p. 606) has discussed the question of spelling, several authors 

 having adopted Midas instead of Mydas. The exact origin of the 

 generic name is not clear, and he supports Mydas, with the family 

 name MYDAIDJE, and these terms are also adopted in the Kertesz 

 Catalogue and in Willistou's Manual. 



Table of Genera. 



Proboscis short; labella terminal, triangular, compressed ; 

 hind tibise generally Avith a spur; anal segment in 

 $ without a wreath of spines ................. . MYDAS, F. 



Proboscis long ; hind tibiae without spur ; anal segment [Gerst, 



in $ with a wreath of spines .................... LEPTOMYDAS, 



Genus MYDAS, F. 



Mydas, Fabricius, Ent. Syst. iv, p. 252 (1794) ; Macquart, Hist. Nat. 

 Dipt, i, p. 273 (1834) ; ]d., Dipt. Exot. i, pt. 2, p. 10 (1838). 



GENOTYPE, Musca clavata, Drury; by Latreille's designation 

 (1810). 



Head broad, short transverse, as broad as thorax, neck short ; 



