495 



widest near the base, and gradually tapering to a point at the apex, not 

 conspicuously contracted beyond the middle (Figs. 51, 52). 



Measurements 



Length 19 mm. 



Length of abdomen 14 mm. 



Length of gills 9 mm. 



Width of gills 1.5 mm. 



Length of median lobe 2 mm. 



Width of median lobe 5-1.5 mm. 



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



Head metallic green and brown, often more or less bronze; me- 

 dian lobe of the labium subquadrangular, with the usual cleft; prox- 

 imal segment of the antennae with pale spot at the distal end, the re- 

 maining segments dark ; postclypeus dull metallic brown, the anteclyp- 

 eus, labrum, and the exposed portions of the mandibles, their 

 trochantins, and the genae, shining yellow ; eyes slate-gray ; occipital 

 and postgenal regions wholly yellow. 



Thorax dull brown and yellow ; caudal margin of the pronotum 

 entire, the caudal lobe narrow and not convex; cephalic lobe much 

 longer and possessing a median, circular, black spot; median lobes with 

 irregular H-shaped black or dark marks, one to each lobe ; proepimeron 

 distinct, pale brown, black on the dorsal margin; mesosupraepisterna 

 dull metallic brown, sometimes greenish, with the lateral fourth yellow ; 

 mesopleural suture with a broad yellow stripe; mesepimeron almost 

 entirely brown, with the exception of the cephalic shoulder; mesinfra- 

 episternum with the dorsal half brown or greenish in older specimens 

 and with a median spot in younger individuals, the remainder of the 

 sclerite pale ; metepisterna with triangular brown spots adjacent to the 

 wing, bases; metapleural suture and the metepimera pale buff; post- 

 coxal areas pale yellow, without dark spots ; paraptera crescentic, the 

 caudal margins faintly emarginate; legs striped, the coxae and the 

 trochanters buff, the femora pale yellow with two black or dark brown 

 stripes ;, tibiae with a single brown stripe including one of the two rows 

 of setae ; tarsi and claws black ; front femoral rows of setae containing 

 three and eight setae respectively ; wings clear, the postnodal cross-veins 

 about eleven, and Mo originating between the second and third in the 

 front wing and between the first and second, usually near the second, 

 in the hind wing. 



Abdomen mostly yellow in recently emerged specimens, dark me- 

 tallic green or brown in older ones ; dorsum of the first tergum brown 



