THE SUBFAMILY LIBELLULIN^E. 337 



colour extending up and down along the sutures, but only continuous behind the first 

 suture ; on the ventral surface are one or two more yellow spots. Legs black, the 

 front coxee and base of the femora yellow beneath. Abdomen red, the base black as 

 far as the carina on the second segment, with a transverse yellow stripe on the first 

 segment, the sutures very narrowly black, the terminal segments, except sometimes a 

 narrow stripe on the base of the eighth, entirely black ; segments 3-7 with a rather 

 indistinct blackish dot on each side of the dorsal line just before the suture. Wings 

 more or less clouded hyaline, with dark brown nervures and pterostigma, a little 

 clouded along the lower antenodal subcostal space and the lower basal cell at the base. 

 Wings with 15-16 antenodal and 12-14 postnodal nervures, the first two or three 

 postnodals not continuous ; triangle small, more or less oblique, and placed on a level 

 with that of the hind wings or a little beyond, followed by two rows of cells increasing 

 (on one side of one specimen by three cells increasing), no supratriangular nervure and 

 only one cross nervure in the lower basal cell in both fore and hind wings, subtrian- 

 gular space consisting of two or three cells; hind wings with 13-15 antenodal and 

 11 postnodal nervures, the first two postnodals not continuous ; triangle placed at 

 about one fifth of the distance between the arculus and the end of its lower sector, 

 followed by two rows of cells increasing ; membranule very small, whitish. 



Female. — Similar, but with the pale markings of the pleura dull flesh-colour rather 

 than yellow ; the abdomen is of a dull reddish brown, the black markings not being 

 very sharply defined, and more extended on the sutures and along the lateral carinas ; 

 there are sometimes two cross nervures in the lower basal cell of the fore wings, and 

 the traversed triangle is followed indifferently by two or three rows of cells increasing, 

 or by a row of three cells followed by a series of two increasing. In one female the 

 lower sector of the arculus falls on the base of the triangle a little before its extremity. 



Bab. Solomon Islands, Santa Anna (1 male), and Alu (1 male, 2 females). 



Allied to A. auatuomotata, Brauer. 



Chalcostephia flavifrons. 



Long. corp. 35 millim. ; exp. al. 62 millim. ; long. pter. 4 millim. 



Male. — Face yellow, upper part of clypeus coppery green, shading into blue on the 

 summit and on the frontal tubercle ; tips of mandibles, suture of labium, and back of 

 head black, the latter with about three small yellow spots on each side behind the 

 eyes. Thorax, abdomen, and legs dull black, the thorax with a slight bluish-grey 

 pulverulence, base of the femora with a reddish-brown spot on the inside. Wings of a 

 slightly brownish but very iridescent hyaline, the extreme tips brownish, pterostigma 

 brown, palest in the centre between brown nervures, the upper nervure very thick ; 

 membranule very small, blackish, with a white dot in the middle. 



Hab. Angola. 



vol. sii. — part ix. No. 12. — August, 1889. 3 c 



