76 FAUNA HAWAIIENSIS 



Wings with i6 — 22 post-cubital cellules. Upper side of the quadrilateral about \ 

 the length of lower in the front wings, somewhat longer in the posterior pair. Post- 

 costal area with either a single row of cellules, or with a double row for a considerable 

 part of its length, extremely variable in the number of cells that are divided. 



t superior appendages terminating above in a stout hook very strongly curved 

 inwards, below this is a distinct but much smaller black tooth, and on the lower margin 

 inwardly nearly half-way between the latter tooth and the base of the appendage is 

 a third very minute tooth or tubercle. The appendages themselves more or less 

 red, the teeth black. Inferior appendages red with black tips curved upwards and 

 inwards. 



$ superior appendages generally black, sometimes red, pointed ; valvules more or 

 less pale, their appendages generally dark. 



Length of abdomen 33 — 40 mm. ; posterior wing 25 — 28*5 mm. ; expanse 57 mm. 



Allied to^. deceptor but generally larger and with the nervuration of the postcostal 

 area more complicated. The t is very distinct by the form of the superior appendages 

 which are much more strongly curved inwards at the apex, and also by the position of 

 the second tooth which, if the appendage be viewed inwardly, is seen to be situated 

 about in the middle of its greatest height, whereas in A. deceptor the tooth is situated 

 at the lower angle. The bright colour of the pterostigma is also a useful character. 



Hab. Kauai, widely distributed (2000 — 4000 ft.). 



(22) Agrion oceanicum M'^Lachl. 



Megalagrion oceanicum M'^Lachl., Ann. Nat. Hist. (5) xii. 1883, p. 239 (<^). 



Female with the wings, &c. as in the Z, which it resembles in most respects, but 

 the abdomen is stouter and the amount of black colour is more extensive than is usual 

 in that sex. Posterior margin of the prothorax strongly raised, angulate in the middle, 

 and fringed with long hairs. (Plate V. figs. 14 & \\a.) 



Hab. Island of Oahu, common and widely distributed, frequenting the streams of 

 both the mountain ranges. 



(23) Agrion blackburni M'^Lachl. 



Megalagrion blackburni M'^Lachl., Ann. Nat. Hist. (5) xii. 1883, p. 238. 



(Plate V. figs. 15 & 15 «.) 



Hab. Maui, Lanai (Scott B. Wilson), Molokai and Hawaii (windward side). 

 Common generally. 



