DIPTERA. 449 



trees to attract moths. They feed on over-ripe fruit and 

 other vegetable substances. 



The larvae are found in pools and in decaying vegetable 

 matter ; they have two pairs of spiracles, one at each end of 

 the body. The pupse are free. 



Only four species of false crane-flies have been found in 

 the United States ; these belong to the genus RhypJius 

 (Rhy'phus). 



Family ORPHNEPHILID^E (Orph-ne-phiri-dae). 



The Solitary-midge. 



Only a single species of this family, Orphnephila testacea 

 (Orph-neph'i-la tes-ta'ce-a), is known to occur in North 

 America. This is a small fly measuring about one eighth 

 of an inch in length, with a wing-expanse of one third inch. 



The antennae are short, about as long as the head, and 

 nearly of the same structure in both sexes ; the segments of 

 the antennae except those at the base are slender and are 

 clothed with a few short hairs. The ocelli are wanting. The 

 compound eyes are large and meet in front in both sexes.' 

 The wing-veins are well developed on all parts of the wing ; 

 vein II ends in the margin of the wing before the end of 

 the basal third ; vein III is two-branched, the first branch 

 ending in the margin at the end of the second third of the 

 wing and the other branch near the apex of the wing ; vein 

 V is two-branched, the branches separating at the end of the 

 basal third of the wing and near the cross-vein III-V ; the 

 fork of vein VII and the cross-vein V-VII are near the end 

 of the basal fourth of the wing. 



The transformations of this insect are unknown. 



Family BIBIONID.E (Bib-i-on'i-dae). 

 The March-flies. 



In these flies the body is comparatively robust, and the 

 legs shorter and stouter than in most of the families with 

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