MAT PLIES AND MIDGES OP 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 (flg.l7), about 16 mm. in 

 length, 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 constructed. 

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

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

 tube by the undulating motion of its body. 



Pupa. The pupa resembles very much that of T h a 1 a s - 

 s o m y 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 (fig.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 armature of the posterior margin 

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

 other segments resemble this arrangement, but the spines become 

 gradually shorter cephalad so that on the first segment the spines 

 are replaced by 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 

 (fig.lG). 



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

 excepting femora, black.' Length 3.5 to 4 mm. 



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

 -slightly infuscated, palpi deep brown, the basal joint and basal 

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

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

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

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

 . metanotum black. Upon the yellow field of the dorsum and 

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

 Abdomen pale yellowish 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 pair 

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

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

 of all femora also yellow. Legs microscopically hair}', fore tibiae 

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

 spurs; pulvilli and empodium present; fore metatarsus about 0.6 

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

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



