842 AN INTRODUCTION TO ENTOMOLOGY 



Family MYDAID^ 



The Mydas-Flies 



The Mydas-flies rival the robber-flies in size, and quite closely 

 resemble them in appearance. As in that family, the vertex of the 

 head is hollowed out between the eyes; but these flies can be 

 distinguished by the form of the proboscis, which bears a pair 

 of fleshy lobes at the tip, by the form of the antennae, which 

 are four-jointed, long and more or less clubbed at the tip 

 (Fig. 1090), and by the peculiar venation of the wings (Fig. 

 109 1), vein Ml terminating at or before the apex of the wing, 

 and the branches of vein R coalescing near the apex of the 

 wing in an unusual way. 



The adults are said to be predacious. The larvffi of some 

 species, at least, live in decaying wood, and some are known 

 ^1090! t*^ P^^y upon the larvag of beetles. 



The family is a small one, there being only about one 

 hundred known species, of these nearly fifty have been found in 



M + : 



Fig. 1091. — Wing of Mydas. 



North America, but most of these occur south of the United States. 

 The family includes the largest known Diptera. 



Family APIOCERID^ 

 The Apiocerids 



This family includes only a small number of species, which are 

 rare and occur in the Far West. The}' are rather large and elongate, 

 and are found upon flowers. 



The head is not hollowed out between the eyes; the ocelli are 

 present; the antennee are three-jointed, with or without a short simple 

 style; the proboscis is not adapted for piercing. The radial sector is 

 usually three-branched, but sometimes it is only two-branched; all 

 of the branches of vein R end before the apex of the wing (Fig. 1092) ; 



