928 CHARLES PAUL ALEXANDER 



LXXII, 387) with dorsal terebra elongate, almost straight or very slightly upturned; eighth 

 segment with dorsal pentagon of spine-tipped lobes quite as in male. 



Ormosia meigenii (O. S.) 



1859 Erioptera meigenii 0. S. Proc. Acad. Nat. Sci. Phila., p. 226. 



Ormosia meigenii is one of the commonest species of the genus, occurring 

 in small dancing swarms in early spring. Larvae of this species were 

 taken on April 10, 1914, in organic mud from Needham's Glen, Ithaca, 

 New York. An adult female emerged on May 4. 



Larva. Length, 6.5 mm. 



Diameter, 0.5-0.6 mm. 



Color, light yellow. 



Form elongate, terete. Spiracular disk (Plate LXX, 379) about as in 0. nubila, dorso- 

 median lobe the smallest, ventral lobes with brown lines rather close together, the distal 

 line the broadest; lateral lobes with lines rather short, not contiguous at their distal ends 

 and not extending past midlength of spiracles; dorso-median lobe with marks oval, solidly 

 dark brown. Lobes fringed with moderately long, yellowish setae, which are almost lacking 

 at extreme tips; disk between spiracles unmarked. Spiracles large, transversely oval, 

 ssparated by a distance a little greater than the long diameter of one. 



Head capsule and mouth parts almost as in 0. nubila; mandible with the long, slender 

 teeth of that species. 



Pupa. (Described from a cast skin.) 



Cephalic crest consisting of low, rounded lobes, each with a seta on anterior lateral face. 

 Pronotal breathing horns of moderate length, flattened, a little narrowed toward tip, outer 

 margin with fine tubercles. Mesonotum not so declivitous as usual in the genus, with tiny 

 roughenings at crest; the usual two setae at lateral angle of thorax present, another above 

 each wing, and four more in a transverse row at level of axilla of wing; a seta on mesonotum, 

 close to median line, just below crest. Middle legs much shorter than fore and hind legs. 



Subterminal rows of setae on abdominal segments consisting of slender, acute spines, 

 with a few setae interspersed; on pleura the spines few in number. Spiracles elongate, 

 tubular. Female cauda with tergal sheaths very long, sternal sheaths short, their tips 

 blunt; on dorsum of eighth abdominal segment five small unarmed tubercles, which are 

 blunt or nearly so, anterior pair more widely separated than posterior pair. (In the shape 

 of the cephalic crest, the breathing horns, and the declivity of the mesonotum, this species 

 resembles 0. nigripila; but the arrangement of setae on the abdomen, and the great reduction 

 and unarmed condition of the lobes on the eighth abdominal tergite, are distinctive.) 



Nepionotype Ithaca, New York, April 10, 1914. 

 Neanotype. Cast pupal skin, Ithaca, May 4, 1914. 



Genus Helobia St. Farg. et Serv. (Gr. marsh + 1 live) 



1825 Helobia St. Farg. et Serv. Encyclop. Method. Ins., vol. 10, p. 585. 



1830 Symplecta Meig. Syst. Beschr., vol. 6, p. 282. 



1865 Idioneura Phil. Verh. Zool.-Bot. Ges. Wien, vol. 15, p. 615. 



1886 Symplectomorpha Mik. Wien. Ent. Zeitung, vol. 5, p. 318. 



