MAY FLIES AND MIDGES OF NEW YORK 55 



Head flat, almost orbicularly rounded, limuloid, the infero- 

 lateral margins thin, flat, flaring, fringed with decurved hairs. 

 Eyes distinctly dorsal, the lateral margins of the head projecting 

 beneath them'. Antennae minute, hardly longer than the head, 

 the basal segments brown and the remainder pale. 



Mouth parts as shown in figs. 12h, 13f and 14n. 



Prothorax with its declined and flaring lateral margins decur- 

 rent upon the sides of the mesothorax ; legs short ; femora much 

 flattened, and with well-developed posterior fringes of hair ; simi- 

 lar fringes on middle and hind tibiae, but scarcely developed of 

 fore tibiae. 



Abdomen rather short, strongly depressed, and much tapering 

 beyond the 7th segment; lateral spines on segments 2-9, on 3-5 

 minute, on 6-9 strong, straight and sharp, longest on 7 and 8, the 

 tip of that on 8 reaching the level of the middle of the 9th seg- 

 ment. Segments of the abdomen diminishing slightly in length 

 to the 7th, the 8th and 9th, then successively a little longer ; 10th 

 produced in a rounded posterior lobe. 



Gills represented on segments 1-7, on 1-6 double, consisting of 

 an anterior protecting lamina and a posterior basal one, mar- 

 gined with respiratory filaments, whose tips are visible at the 

 inner margin of the lamina. Gill lamella on 1 oblong, somewhat 

 oblique, with a small lobe beside the basal attachment on the 

 side next the median line of the body; on 2-6 similar, becoming 

 somewhat more elongate and less oblique; posterior lamina with 

 its outer two fifths cut into a border of 1-2 branched respiratory 

 filaments. On segment 7 there is a simple linear lanceolate fila- 

 ment (representing the anterior lamina only) whose tip reaches 

 the level of the apex of the 9th abdominal segment. 



Setae long, slender and very hairy for more than half their 

 length, the hairs distinctly shorter externally; tips pale, whitish, 

 ringed with darker and nearly destitute of hair. 



Coloration olivaceous or greenish brown, darker on head on 

 sides of prothorax and on dorsum of abdominal segments 6 and 

 10. On the head there is a pale spot (before the middle ocellus, 

 another one Ibetween each lateral ocellus and the eye, and an 

 oblique pale streak extends from the eye to the margin below it. 

 A pale, narrow middorsal line extends from the rear of the head 

 to the metathorax. The legs are pale, with two broad light-brown 

 bands on each of the femora. On each of the exposed abdominal 

 segments is a transverse pale basal area which includes on each 

 segment, except the 6th, a pair of brownish dots ; these dots are. 

 elongated into longitudinal dashes on segments 8 and 9. Abdo- 

 men beneath conspicuously barred with brown (pl.9, fig.3), 

 one angulated bar on each segment, the bars interrupted in the 



