NO. 1571. DRAGONFLIES OF BURMA AND SIAM— WILLIAMSON. 283 



space in front wino^ with 3, in hind wing with 2 additional cross veins; 

 1 or 2 supertrianguhxr cross veins in front wing, 1 in hind wing; 6-8 

 cross veins between ]Mi_3 and M^ in front wing, 4-5 in hind wing; anal 

 triangle 5-celled. (See fig. 9.) 



Lower lip dull brownish, the adjacent portion of the rear of the 

 eyes dull yellow; remainder of the head black, marked mth yellow 

 as follows: Upper lip wdth a superior spot on either side, separated 

 by more than their own length; .base of mandibles, margined with 

 black; rliinarium; a very small inferior lateral spot on nasus; a 

 narrow superior line on the frons in front; the anterior half of the 

 frons above, this pale area nearly or quite divided by a broad low 

 triangle of black continuous with the basal black of the frons. Occi- 

 put high, rounded, with short cilia. 



Prothorax ricli dark brown. Thorax of the same color, paler 

 below, marked with light yellow as follows: A wide mesothoracic 

 half collar, divided at the median line; short, widely divaricate, 

 cuneiform stripes on either side above, beginning just in front of the 

 antealar sinus and reacliing about half way to the mesothoracic half 

 collar; antehumeral stripe entirely wanting, not represented by a 

 spot or line; mesepimeron with a stripe a little more than 1 mm. wide, 

 of nearly uniform width for its entire length; just behind the extreme 

 upper end of this stripe a minute inconspicuous spot (probably this 

 is variable and specimens with a row of spots in the black area would 

 not be surprising) ; metepimeron with a stripe not quite 2 mm. wide 

 at its widest part; a spot between the front mugs, and a transverse 

 row of 3 spots in juxtaposition between the bases of the front and 

 liind wings. Legs darlv, brown, apices of femora and the til)ia? black. 



Abdomen brown anteriorly, black posteriorly, marked with yellow 

 as follows: 1 and 2 obscurely marked, 1 with a dorsal basal spot, 2 

 with a dorsal median spot, the auricles dull yellowish tipped mth 

 black; basal dorsal rings on 3-7, occupying two-fifths of 3, one-third of 

 4-6, and nearly one-half of 7; these yellow areas minutely punctate 

 with black and on 3-6 divided posteriorly in the median line by the 

 encroaching black; on 7 the yellow is produced slightly posteriorly in 

 the median line; 8 with a small obscure basal lateral spot, a hint of 

 which is found on 9; 10 with an obscure dorsal median greenish spot, 

 the spot itself with a median black spot; appendages black; abdomen 

 beneath dark, base of 3, vesicle, and portion of apices of genital 

 hamules pale. (See fig. 10.) 



Genital lobe represented on the margin of the segment by a low 

 ridge w^th 4-6 short black teeth; anterior lamina prominent, the 

 median third produced posteriorly as a smoothly rounded tubercle; 

 hamules thin, plate-like, extending well beyond the vesicle of the 



