MAY FLIES AND MIDGES OF NEW YORK 271 



dark brown on the under surface and pale above, but little longer 

 than wide, each with 7 or 8 long brown setae at apex. 



The larva constructs an oval case (fig.17), about 16 mm. in 

 lenoth the thick outer coat of which is gelatinous, transparent; 

 the^inner tube in which the larva lives is dark brownish green, 

 owing to the material (SpirogjTa, etc.) of which it is constiiicted 

 When it is disturbed the larva escapes from a hole at the end ot 

 the tube. Normally it keeps up a water circulation through the 

 tube bv the undulating motion of its body. 



Pupa. The pupa resembles very much that of Thalas- 

 s o m v i a f u s c a . It is dusky yellowish brown in color, the ven- 

 tral surface somewhat lighter. The respiratory organs are 

 slender, about one fifth as long as the thorax, the surface covered 

 with distad projecting scales (flg.l3). Upon the dorsal surface 

 of the thorax are several pairs of short black setae. The dorsal 

 surface of all abdominal segments is finely sprinkled with very 

 minute short, dark setae; the aruiature of the posterior margin 

 of the seventh segment is shown in fig.15; the margins of the 

 other segniients resemble this arrangement, but the spines become 

 o-raduallv shorter cephalad so that on the first segment the spines 

 are replaced bv short tubercles. The anal fin is broad and some- 

 what rounded 'at the apex, with two pale slender setae near the 

 apex, and with a margin of moderately long, pale, matted hairs 



Imago, female. Yellow; antennae, palpi, metathorax, and legs 

 excepting femora, black. Length 3.5 to 1 mm. 



Head and proboscis vellow, the latter with black tip; occiput 

 sliohtly infuscated, palpi deep brown, the basal joint and basal 

 one half of second joint of antenna yellow, the remaining joints 

 deep brown. Thorax deep vellow, with three deep brown lines, the 

 middle one divided bv a yellow hair line, a dark brown spot in 

 front of base of wing; pleura and scutellum yellow, pectus and 

 metanotum black. TTpon the yellow field of the dorsum and 

 npon the scutellum are several irregular rows of short black hairs. 

 \bdomen pale vellowish brown, disk of each segment a little 

 darker the posterior margin dorsally with a narrow, ventrally 

 with a wider, yellow fascia. Hairs black. Genitalia yellow and 

 inconspicuous. Fore pair of coxae yellow, middle and hind pan- 

 fuscous; all legs black; fiexor surface of all femora, except ex- 

 treme tip, yellow. The extreme basal portion of extensor surface 

 of all femo'ra also vellow. Legs microscopically hairy, fore tibiae 

 with one, and middle and hind tibiae each with two small black 

 spurs- jnilvilli and cn.podium present; fore metatarsus about 0.6 

 as lono- as its tibia. The hyaline wings are broad and long, extend- 

 ing bevond the tip of the abdomen, the veins distinct, the anterior 



