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. 



Lcusth of gills 5.5 mm. 



Width of gills 1 .(> nmi. 



Length of mctathoracic wing-eases. . . .4 mm. 



Length of median lohc 2 mm. 



Width of median lohc 5-1.8 mm. 



Adult; Male. — Color, pale bine or oran.sjc. and black. 



Head blue or orange, ami I)lack ; mouth-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. 



Thora.x 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 

 frequentlv 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 

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

 thora.x pale blue or orange, butl-colored below ; paraptera trapezoidal, 

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

 legs usually buff, the femora with rm indefinite dorsal brown line and 

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



