68 DIPTERA OF MINNESOTA. 



A very small family of flies, containing only a few species, pos- 

 sibly less than twelve in the United States. Rhyphus fenestralis, 

 as its name indicates, is frequently found on windows. Comstock 

 has observed species of this family feeding at night-fall on sugar, 

 placed on trees to attract moths. They are also said to feed upon de- 

 caying fruit and other vegetable matter. The small larvae are worm- 

 like, legless, and are found in pools of water, brooks, puddles, in decay- 

 ing wood, rotten fruit and cow dung. Our illustration (Fig. 56), 

 shows the appearance of Rhyphus punctatns, Fab., taken in Minnesota 

 in May, and typifies the imagoes of this group. The flies are small, 

 mosquito-like, and look like small editions of Crane Flies (Tipulidae) , 

 but lack the V-shaped suture on the thorax, which characterizes the 

 latter family. 



Minnesota species so far taken : Rhyphus punctatus, Fab. 



ORPHNEPHILIDAE. 



Solitary Midges. 



The members of this family are very rare, and belong to one genus, 

 Orphnephila. Very little, if anything, is known of their transform- 

 ations. The flies are small, brownish or yellowish, and found in the 

 neighborhood of streams. One species occurs in Great Britain, and 

 but one, according to Comstock, 1895, 0. testacca, in the United States. 



BIBIONIDAE. 



March Flics. 



Perhaps "Spring Flies" would be a better appellation for these 

 insects, since as far as Minnesota is concerned they rarely appear in 

 March, some species being first observed when spring is quite well 

 along, and a few do not appear until autumn. They are well illus- 

 trated in Figs. 57 and 58, and for the most part are dark colored, 

 though the legs of the females of some of the species are brightly 

 colored ; some species are yellow, and a very common species, Bibio 

 albipcnnis (see illustration), one of the earliest observed here, has 



