438 NEW YORK STATE MUSEUM 



ing, the females seemed to remain less of the time in the vicinity of the 

 water. The female makes a succession of sweeps back and forth near 

 the head of some little riffle, striking the water, after short flights, again 

 and again near the same place, leaving her eggs in it. 



Imagos, living and mature, are of a rich, deep green color with the 

 usual oblique stripes of blackish brown. Unfortunately, the color fades 

 readily, even where daylight is excluded. The few imagos which I took 

 the time to gather were nearly all netted while resting on a water pipe 

 which crosses a riffle just below the railroad bridge. 



The nymphs Were very common in the sandy bed of the creek. A 

 great many were raked up and sifted out with a sieve net while collecting 

 for other material. The cast skins were abundant along the banks 

 through the months of June and July, sticking to whatever support 

 offered, within a foot of the edge of the water. 



Nymph, (pi. 18, fig. 5) Total length 27.5 mm; abdomen 17.5 mm; 

 hind femur 5 mm; width of head 5 mm, of abdomen 7.5 mm. 



Legs, genae, sides of the antennae, and lateral margins of the abdomen, 

 hairy ; the general dorsum nearly bare ; well developed burrowing hooks 

 at the apices of the fore and middle tibiae. 



Abdomen oval in outline as seen from above, abruptly narrowed on 

 the ninth segment ; the loth segment one third shorter than the ninth; 

 the lateral abdominal appendages two thirds as long as the others; very 

 short, subequal lateral spines on the seventh to the ninth segments ; 

 dorsal hooks represented on the second to ninth segments by blunt rudi- 

 ments, which are erect on the front and posteriorly directed on the hind 

 segments, each surmounting a low transverse ridge, which extends across 

 the dorsum and disappears down on the sides on each segment. Anterior 

 two thirds of each segment, including this ridge, prickly granulate; 

 posterior third polished, shining, smooth. 



Mentum of labium one third longer than wide, dilated beyond its 

 basal third and upturned so as to be flaring upward at its edges ; median 

 lobe distinctly rounded and fringed with flat scales, and bordered be- 

 sides with a row of low, broad, rectangular teeth; lateral lobe incurved, 

 rounded on the apex and not bearing a terminal hook or sharp angle, its 

 internal margin bordered with a row of 12 to 15 low teeth. 



Color greenish or brownish, with paler and darker mottlings; apical 

 pale rings on all femora; a pair of transversely elongate whitish spots on 

 the dorsum of the seventh abdominal segment, repeated on the eighth seg- 

 ment, but there divided into two spots each side; a whitish spot each 

 side of the loth segment beside the base of the superior appendage; tips 

 of all the abdominal appendages whitish. 



The nymph is a rapid burrower, trailing along at slight depth through 

 nearly clean sand under the currents, often leaving a faint line behind 

 showing where the tip of the abdomen, upturned for respiratioHj has 

 pushed the sand grains aside. 



