694 FAUNA HAWAIIENSIS 



1. Superior appendages of the $ abdomen short, the inferior ones extending 



behind them ; most of the abdominal segments dark and metallic, and 

 at most with a pale band at the base ; lower appendages bidentate at 



the apex or obliquely truncate in side view A. xanthomelas, pacificum, nigra hamatum. 



Without some or all of the above characters 2. 



2. Superior appendages generally shorter than the lower and with a black tooth on 



the inner side towards the base, this tooth being usually directed upwards ; 



abdomen largely red A. oresitrophum, orobates, leptodemas, calliphya. 



Without some or any of these characters 3- 



3. Legs mostly dark brown or black ; abdomen usually black or pitchy and 



metallic, rarely with red segments behind the two basal ones ; insect often 

 with more or less whitish pruinosity ; upper appendages in lateral view 



emarginate at apex so as to form two apical processes or teeth 



A. koelense, asteliae, amaurodytiim, eudvium, adyUim. 

 Without some or all of these characters 4- 



4. Upper appendages extremely long and forcipate, dilated only at the extreme 



base A. nesiotes. 



Appendages not so formed 5- 



5. Upper appendages turned outwards, their broad surface exposed in dorsal 



aspect ; apical abdominal segment strongly and obliquely raised from 



base to apex A. oahuense. 



Without these characters 6. 



6. Postcostal area of front wings with a single row of cellules, rarely with a few 



divided, to form a double row; abdomen slender or very slender 



A. deceptor, vagabundum, kauaiense, molokaietise, Jugonim. 

 Postcostal area of front wings always with a double row of cellules for a 

 considerable part ; species of large size and the abdomen relatively stout 

 compared with the above species A. oceantcum, blackburni, heierogamias. 



The last three species form the genus Megalagrion of McLachlan, but individuals 

 of some of the preceding group might be included therein. 



(i) Agrion culver ti, sp. no v. 



Head dull black, apex of clypeus and labrum, orbits to the height of the antennae, 

 mouth-parts and a spot on the basal joint of the antennae yellow or cream-coloured. 

 Postocular spots orange, not connected. Prothorax yellow in front and at the sides. 

 Dorsum of mesothorax black with purplish metallic lustre, a spot on each side in front 

 connected with a sutural line not reaching the hind margin, a spot on each side near this 

 margin, a band on the sides of the mesothorax extending back from the middle coxae 

 for less than half its length, but represented by a detached spot near the hind margin, 

 the whole lower part of the mesopleura extending back from the posterior coxae to the 

 hind margin, except a spot posteriorly, yellow. Median longitudinal ridge of mesonotum 

 reddish. Legs with the femora and tibiae sordid brownish or fuscous above, beneath 

 and the trochanters yellow, the coxae infuscate in part. Abdomen black or pitchy, with 

 a green metallic lustre, basal segment yellow at the sides and with very narrowly pale 

 apical margin, third to the seventh with narrow yellow basal band, terminal segment 

 reddish, but sordid in parts. 



