40 J ov^rnal of Agricultural Research voi. xiii. no. i 



As mating was observed in the orchards, and as the bodies of most 

 of the female stoneflies taken here contained eggs, it is evident that 

 the females must return to the river after feeding to deposit their eggs. 

 These eggs hatch in the water, and the nymphs develop slowly, the adults 

 emerging in the spring as soon as the weather becomes warm. Whether 

 the n3^mphs complete their development in a single year, or require two 

 years or more, is not known. 



DESCRIPTIONS OF STAGES 



Egg. — Oviposition was not observed; nor were eggs found in the v/ater; but eggs 

 dissected from the body of the female were approximately spherical and about 0.2 

 mm. in diameter. 



Nymph (PL 3, C). — The full-grown nymph is about 10 mm. long, exclusive of the 

 antennae and cerci. The prothorax and abdomen are dull, dark brown, the head is a 

 lighter brown, the eyes black, and the meso thorax, metathorax, and all appendages 

 a very light brown. The filamentous antennae are about 6.5 mm. long and the ab- 

 dominal cerci about 8 mm. long. The legs are fringed with long hairs. No gills 

 were present on the specimens collected, which were just ready to emerge and may 

 have lost them. 



Adult (PI. 3, C; PI. 4, A). — The original description of the adult is given herewith: 



Head dull black; antennae brown; prothorax dull black, anterior margin, and usually 

 the lateral margins, narrowly reddish; base of mesothorax reddish, rest of body black; 

 legs yellow-brown, knees rather darker. Wings dull hyaline, without marks, or an 

 indistinct cloud near the middle, hind pair hyaline, veins brown. Prothorax rather 

 broader than long, a transverse sulcus in front, on the disk are scattered small flat 

 tubercles or scars; second joint of tarsi as long as first, tips of tibiae with a pair of 

 minute spines; ventral plate of the female is nearly semicircular. Wings long, slender, 

 subcostal with several cross- veins to margin near tip, and a few near base, radial 

 sector with but one fork beyond the anastomosis, the vein from the discal cell arises 

 near the radial sector, pterostigmatic region long, with but one cross-vein. 



Length to tip of wings, 12 mm. 



Pullman, Wash., April (C. V. Piper, R. W. Doane).' 



DESCRIPTION OF MOUTH PARTS 



Since the structure of the mouth parts determines the economic im- 

 portance of an insect of this type, a detailed description of these will 

 not be out of place here. 



ADULT (PL. 4) 



Labrum. — Subquadrate, somewhat broader than long, sparsely covered with setae; 

 sides convex and heavily chitinized; distal margin slightly concave. 



Mandibles. — vSubtriangular, the outer margin slightly rounded, the cutting edge 

 provided with a series of strongly chitinized teeth, which are unlike on the two mandi- 

 bles. The right mandible has a sharply pointed tooth at the outer edge, behind 

 which are three bladelike teeth and a protruding grinding edge. The left mandible 

 has a row of three sharply pointed teeth, behind which are two bladelike teeth, the 

 second being serrate, and a grinding edge. 



Maxill-'E. — Of the usual biting type. Galea digitiform, lacinia tapering, provided 

 distally with two chitinous teeth, one longer and heavier than the other, and with a 

 row of spines along the inner margin. Palpus four- jointed, covered with many setae. 



• BANKf5, Nathan, new gbnera and species of nearctic netjropteroid insects. In Trans. Amer. 

 Ent. Soc., V. 36, DO. 3, p. 344. 1900. 



