922 CHARLES PAUL ALEXANDER 



The immature stages of Erioptera (Mesocy phono) cdloptera (Say) and 

 E. (M.) parva O. S. are spent in wet mud along the banks of streams 

 and other bodies of water. The species discussed below as Erioptera 

 (Mesocyphona) species (near knabi), was reared from the sandy margins 

 of a small prairie stream in Kansas. 



Erioptera (Mesocyphona) species (near knabi Alex.) 



Adult flies of a small species of Mesocyphona which is close to E. (M.) 

 knabi Alex., of Mexico, were not uncommon along Buckner Creek, a small 

 prairie stream flowing thru Jetmore, Kansas. These adults, especially 

 the females, were photophilous, appearing in considerable numbers around 

 lanterns which were hung in tents pitched along the banks of this stream'. 

 A single pupa found in the muddy sand along the bank of the creek on 

 July 20, 1917, emerged as an adult on the 22d. The following general 

 characters of the species may be noted: 



Pupa. Labrum small, apex rather sharp. Labial lobes squarely truncated, with lateral 

 angles subacute. Sheaths of maxillary palpi slender. Pronotal breathing horns moderately 

 long, cylindrical, curved slightly forward, enlarged outwardly, blunt at tips. Mesonotum 

 at crest rather tumid and with a few long hairs inserted on stout black tubercles. Leg sheaths 

 with middle tarsi the shortest, hind tarsi the longest. 



Neanotype. Jetmore, Hodgeman County, Kansas, July 22, 1917. 



Genus Ormosia Rondani (Gr. chain) 



1856 Ormosia Rond. Dipt, Ttal. Prodr., vol. 1, p. 180. 



1860 Rhypholophus Kol. Wien. Ent. Monatschr., vol. 4, p. 393. 



1863 Dasyptera Schin. Wien. Ent. Monatschr., vol. 7, p. 221. 



Larva.' Form terete, moderately elongated. Spiracular disk squarely truncated, sur- 

 rounded by five subequal lobes which are lined with double marks of brown. Anal gills 

 blunt. Head capsule slender, very dissected, of six narrow bars, four dorsal and two ventral, 

 the ventral bars broader. Labrum narrow, epipharynx hairy. Mandible with teeth 

 moderately elongated. Antenna of the Molophilus type. Mentum without chitinized 

 teeth. 



Pupa.- Cephalic crest setiferous. Pronotal breathing horns rather short and stout, 

 more or less flattened and with a row of tubercles along posterior margin. Mesonotum 

 declivitous, at crest with a flattened, toothed, chitinized plate on either side (in 0. nubila] 

 or with abundant setiferous tubercles. Wing sheaths ending opposite or just beyond tip 

 of second abdominal segment. Leg sheaths varying in length with the different species, 

 middle tarsi the shortest. Abdominal segments with a subterminal transverse row of spines 

 or setae, these occurring on pleura (as small groups of eight to twelve) as well as on tergites 

 and sternites. Lateral spiracles distinct, on segments 2 to 7; dorsum of segment 8 with 



