472 



base of the distal segment ; caudo-lateral margins of the head forming 

 a blunt tubercle. 



Thorax twice as long as broad, a dark lateral line occurring in 

 some individuals, extending from the eyes to the bases of the second 

 pair of wing-cases, though, as a rule, this is much less distinct than 

 in Agrion; lateral margins of the pronotum distinctly elevated, 

 scalloped, and the margins produced at two points on each side to form 

 tubercles (Fig. 23) ; legs without heavy setae, usually light in color. 

 In younger and more plainly marked specimens the proximal half of 

 the femur is dark brown ; this is followed by a light band, beyond 

 which the femur is again brown to the apex ; tibiae with three faint, 

 dark rings, the bases and apices also dark; tarsi light in color except 

 the apical half of the third segment and the tarsal claws, which are 

 usually black. 



Abdomen : lateral keels feebly developed, not armed with setae 

 though ending abruptly on the apex of segment nine in a short blunt 

 tubercle; ovipositor short and extending hardly caudad of the apex of 

 the ninth abdominal segment ; lateral gills three-sided, the median one 

 flat and considerably shorter than the lateral ones ; median gill dark 

 along the axis nearly to the apex and with three dark cross-bands; 

 axes of lateral gills sometimes dark, though more frequently the whole 

 gill is light brown or buft and the three margins are each marked with 

 three dark spots (Fig. 79). 



Measurements 



Length 23 mm. 



Length of abdomen 12 mm. 



Length of lateral gills 9-10 mm. 



Length of metathoracic wing-eases .... 6 mm. 



Length of median lobe 4 mm. 



Width of median lobe 1.3-3 mm. 



There seems to be a great deal of variation in the color markings 

 of the nymph, especially in the amount of dark pigment, and specimens 

 may be taken which are either practically without body markings of 

 any sort or are so dark and plainly marked as to make the collector 

 think he has taken another species. 



Adult; Male. — Color, bronze and metallic green; bases of the 

 wnngs carmine. 



Head metallic bronze; median lobe of the labium subtriangular 

 in outline ; labial palpi broad, the terminal segment black and as long 

 as the fixed hook of the first segment; front, vertex, clypeus, and 



