480 



Thorax slender; the distances between procoxa and mesocoxa, 

 and between mesocoxa and the metacoxa nearly equal ; front femora 

 about half the length of the hind femora and all femora with faint 

 preapical rings of brown; wing-cases short and extending hardly 

 caudad of the second abdominal segment. 



Abdomen with poorly developed lateral keels which are provided 

 with apical spines on segments 5-9; gills (Fig. 50) broad, bluntly 

 pointed, and provided with three conspicuous cross-bands of dark pig- 

 ment, the length of the median gill about four times its greatest width ; 

 ovipositor of the female reaching slightly beyond the apex of the tenth 

 segment. 



Measurements 



Length 16 mm. 



Length of abdomen 12 mm. 



Length of gills 8 mm. 



Width of gills 2 mm. 



Length of metathoracic wing-cases ... 5 mm. 



Length of median lobe 3 mm. 



Width of median lobe 1.5 mm. 



Described from three nymphs received from Dr. E. M. Walker 

 and taken at Prince Edward Island, Canada, Aug. 1, 191 5. 



Adult; Male. — Color, dull brown and buff or yellow. 



Head black, buff below ; median lobe of the labium subquadrangu- 

 lar, the median cleft shallow, the labial palpi broad, the distal segments 

 much shorter than the fixed hook, and brownish at the tips ; antennae 

 uniform black, the first segment pale at the apex; postclypeus black 

 or dark brown, the anteclypeus, labrum, and genae to the level of the 

 fronto-clypeal suture yellow; lateral ocelli with small yellow spots 

 laterad of them; front, remainder of the vertex, occiput, except occa- 

 sionally a transverse yellow stripe from the occipital foramen to the 

 compound eyes, black. 



Thorax dark brown and yellowish buff, the prothorax dark brown, 

 the median lobes of the pronotum with pale lateral margins, and spots 

 on the meson near the caudal margin; caudal lobe of the pronotum 

 black ; proepimeron black ; mesostigmal plates with pale lateral angles ; 

 dorsal carina usually with a pale line, the mesepisterna, except the 

 ventral half of the infraepisternum, black or dark brown; caudo-dorsal 

 angle of the metepisterna dark brown or black; metepimera with an 

 elongate black spot near the ventro-lateral carina and a similar spot just 

 ventrad of the carina ; legs striped, the coxae buff, trochanters black 

 above, the femora black with a narrow pale stripe including the ceph- 



