512 



the remainder pale; third antennal segment longest, the second and 

 fourth about equal, and the first, fifth, sixth, and seventh successively 

 shorter; caudo-lateral margins of the head without heavy setae; 

 labium, when folded, extending caudad between the first and second 

 pair of coxae ; median lobe nearly as broad as long, and with about 

 twelve marginal setae ; lateral setae of the labial palpi two or three. 



Thorax about as broad as long; legs with conspicuous brown 

 bands, the femora possessing two — a broad basal one and a narrower 

 preapical one — the tibiae three, one on base, one on apex, and a l)roader 

 one just proximad of the middle ; tarsi with the usual ventral setae and 

 mostly dark; metathoracic wing-cases reaching the apex of the fifth 

 abdominal segment in mature nymphs. 



Abdomen dark, almost black ; lateral keels feebly developed, 

 hairy; dorsum of the first to the tenth terga with a pale mesal stripe 

 which widens slightly caudad though not as conspicuously as in the 

 n3-mph of violacca or apicalis; gills elliptical, sometimes wholly dark, 

 or smoky, often possessing a broad, transverse, whitish band about the 

 middle and a narrower subapical one ; margins densely pilose but with- 

 out heavy setae and the gills frequently coarsely spotted ; female ovi- 

 positor extending to the apex of .segment ten. 



Mensurements 



Length 12.5 mm. 



Length of abdomen 7 mm. 



Length of gills 6.5 mm. 



Width of gills 3 mm. 



Length of metathoracic wing-cases . . . 3.5 mm. 



Length of median lobe 2.5 mm. 



Width of median lobe 1.25-2 mm. 



Adult; Male. — Color, dark purple or warm brown, sulphur-yel- 

 low, and black. 



Head blue or brown ; median lobe of the labium brown, the me- 

 dian cleft short, obtuse at the base ; proximal segment of the palpus 

 rather narrow, the apical segment black and slightly shorter than the 

 black fixed hook ; antennae black with the exception of the apices of 

 segments one and two, which are pale ; f ronto-clypeal suture lined with 

 brown ; clypeus, labrum, exposed portions of the mandibles and their 

 trochantins, genae, and front to the level of the median ocellus brown 

 or blue ; ocellar triangle, vertex, and the occiput, black, the black area 

 sending a black stripe ventrad from the vertex to each antenna, and 

 another enclosing the median ocellus and extending a short distance 



