532 



and about half the length of the gills; female ovipositor extending to 

 the middle of the tenth abdominal segment, the ventral margins of the 

 lateral valves setose, the row consisting of about eight stout setae and 

 a number of hair-like ones. 



Measiwements 



Length 15 mm. 



Length of abdomen 10 mm. 



Length of gills 6 mm. 



Width of gills 1.8-2.1 mm. 



Length of metathoracic Aving-eascs. .4.5 mm. 



Length of median lobe 3.1 mm. 



Width of median lobe 8-2.3 mm. 



Adult; Male. — Color, dark blue and black. 



Head blue and black ; mouth-parts buff, the median lobe of the 

 labium subtriangular, with a shallow, acute, median cleft, the labial 

 palpi much broader at the proximal end than at the apex ; antennae 

 dark brown or black; postclypeus with a shining black spot on the 

 meson; anteclypeus shining yellow; labrum shining yellow with a black 

 dorso-mesal spot ; exposed portions of the mandibles, trochantins, and 

 genae pale, and a pale stripe above the clypeus extending dorsad to the 

 level of the antennal fossae ; remainder of the front and vertex dull 

 black; postocular spots oval or subcuneiform, the pale line caudad of 

 the ocellar area not distinct ; occiput and postgenae yellow, except a 

 transverse black stripe caudo-ventrad of the postocular spots; com- 

 pound eyes dark brown or black. 



Thorax blue and black, the black usually metallic ; pronotum 

 black, the cephalic lobe with a pale transverse line, the median lobe 

 with a pale spot on the lateral margins and the caudal lobe also with 

 pale margins ; proepimera with black dorsal borders, pale below ; meso- 

 stigmal plates subciuadrangular, the cephalo-lateral angles somewhat 

 elevated, though not as much so as in cariinciilatuui , and the lateral 

 half covered by a yellow spot ; dorsal black stripe regular and covering 

 nearly half of each supraepisternum ; pale stripe of the supraepisterna 

 broadest dorsad of the mesinfraepisterna, extending nearly to the 

 paraptera; mesopleural black stripe of the suture narrowed cephalad 

 c^f the wing bases, broadest shortly caudad of the mesinfraepisterna 

 arid extending across and covering about one-third of the latter; caudal 

 margin of the mesepimera black to the level of the interpleural suture ; 

 metapleural suture with a black spot cephalad of the wing bases; re- 

 mainder of the pleura blue, the postcoxal areas buff, becoming polli- 

 nose ; paraptera black, the cephalic margins pale and a pale spot below 

 the lateral angles ; legs striped, the coxae and trochanters pale, the 



