10 THE IMMATURE STATE OF THE ODONATA 



together; fourth joint shorter than the third; anterior bonier of the fore- 

 head forms a short triangular horn, not excavated above, rounded at tip. 

 about as long as the basal joint of the antenn;v\ 



Mask very extraordinary, extending between the middle legs, as tar as 

 an elevated transverse ridge between the hind legs; basal part long, much 

 bicarinated underneath, enlarged forward, forming at the middle two lobes; 

 palpi comb-like, about as long as the basal part, but narrow, not interlock- 

 ing : the interior edge has six strong teeth, widely separated; the apical 

 tooth very short, the two following very long, the three ^or four) basal ones 

 shorter ; the apical half of all teeth black ; the two longest ones cross each 

 other: movable hook very short, sharp. Prothorax a little narrower than 

 the head : an elevated ridge in front, and an elevated ridge around the 

 whole hind part, which is traversed by another elevated ridge ; stigma 

 large, uncovered : dorsal parts of thorax quadrangular, with an elevated 

 somewhat angular formation of the middle portion ; wing covers reaching 

 the end of sixth segment or a little farther ; the venation is not so far 

 advanced as to be conclusive, but so for as can be seen it seems to be anal- 

 ogous to Macromia ; it shows a blackish spot on the nodus of all wings, a 

 blackish stripe along the radius to the nodus, and two blackish spots on 

 the hind border extending upwards on the wing, and perhaps a blackish 

 border around the basal part of hind wings. 



Abdomen large, ovate, roof-shaped, sixth segment and that following 

 tapering ; side margin very sharp with a fringe of short bristles. The 

 apical half of the abdomen with longer tufts of hairs. Segments of equal 

 length except the last, which is only half as long as the rest ; lateral spines on 

 eighth and ninth segments sharp, straight, on eighth very short, on ninth 

 longer than last segment, black at tip ; the lateral spines belong to the dorsal 

 part of the abdomen just as in Macromia ; dorsal hooks on segments third to 

 ninth ; it is impossible to ascertain whether there is a hook on the second ; 

 hooks compressed, connected with the whole length of segments, their tips 

 pointing towards the end of abdomen, extending beyond the segments; hook 

 of third segment cylindrical : dorsum of last segment slightly inflated in the 

 middle, an indication of a hook; the anal appendages a little longer than 

 the last segment, forming a thick short pyramid, breadth and length equal; 

 the dorsal median as long as the inferiors, triangular, flat, rather roof-shaped, 

 in the male has no inflation ; the inferiors sharp, pyramidal : the laterals a 

 little shorter, flat, triangular ; all villous, with long hairs on inner side. 



