554 



gills consists of three to five broad, black cross-bands and a broad 

 axial band from the bases to the apices ; ovipositor extending to the 

 middle of the tenth abdominal segment. 



Measurements 



Length 16-18 mm. 



Length of abdomen 10.5-12.5 mm. 



Length of gills 5.5 mm. 



Width of gills 1.6 mm. 



Length of metathoraeic wing-cases. . . .4 mm. 



Length of median lobe 2 mm. 



Width of median lobe 5-1.8 mm. 



Adult; Male. — Color, pale blue or orange, and black. 



Head bine or orange, and l^lack ; month-parts buff, the median 

 lobe of the labium subtriangular, the palpi pale; first two segments 

 of the antennae pale, at least much paler than the distal ones, the 

 second segment darker at the tip ; postclypeus black, sometimes with 

 a pair of median pale spots, one on each side of the meson; anteclypeus 

 pale; labrum pale, the dorsal margin with a mesal black spot and 

 two lateral ones, or with a transverse stripe of black including the 

 three spots; exposed portions of the mandibles, their trochantins, 

 genae, and a transverse stripe above the clypeus extending slightly 

 dorsad of the antennae, orange or blue ; remainder of the front and 

 vertex black; postocular spots large, cuneiform, and yellow or blue; 

 postgenae and the occiput largely yellow. 



Thorax orange or blue, and black; pronotum black, the cephalic 

 lobe, a subcircular spot on each median lobe, and the entire caudal 

 lobe blue or yellow^ ; the spots on the median lobes are variable, being 

 freciuently subcircular with an emargination on one side; in younger 

 individuals there are also two smaller spots mesad of the large spots 

 on each mesal lobe ; proepimera blue or yellow, the dorsal margins 

 covered by a black stripe ; stigmal plates triangular, the caudo-mesal 

 angles elevated, and the caudal margins with a blue or yellow stripe; 

 dorsal carina covered by a black stripe, the margins of which are 

 parallel and very straight ; mesopleural suture also with a broad stripe 

 which is widest just caudad of the mesinfraepisternum and extends 

 cephalad and covers the dorsal third of that sclerite; remainder of the 

 thorax pale blue or orange, buff-colored below ; paraptera trapezoidal, 

 black, the cephalic margins and a spot below the lateral angles pale; 

 legs usually iDufT, the femora with an indefinite dorsal brown line and 

 a row of spots, the tibiae with a faint dorsal line or row of dashes; 



