238 Mr. R. McLachlan on the 
discovered. The double row of cellules in the postcostal area 
(and in M. Blackburni the neuration is still more irregular) 
exists only in Hyponeura, and the long tibial spines appa- 
rently show further affinity therewith ; but the coloration is 
opposed, and the anal characters are in accordance with most 
of the other Hawaiian Agrionina. 
Megalagrion Blackburnt, n. sp. 
Wines hyaline in the slightly immature male, tinged with 
fuliginous in the female. Pterostigma surmounting two 
cellules (or two and a half), its lower edge very distinetly 
shorter than the upper, outwardly very oblique, reddish brown. 
Neuration black. Quadrilateral having its upper edge about 
one third the length of the lower in the anterior wings, about 
one half in the posterior (only about one fourth in both pairs in 
the female). A double row of postpterostigmatical cellules. 
Postcostal area with two complete series of cellules, and the in- 
ferior sector of the triangle is irregularly broken, so that there 
is a partially double series in the area between it and the su- 
perior sector. In addition to this the neuration in the apical half 
of the wing is often broken up into double series of cellules, in 
some places simulating interposed sectors. ‘Thirty posteubital 
cellules in the anterior wing, and twenty-three in the posterior 
in the male, thirty-six and twenty-seven in the female. Hight 
or nine cellules between the quadrilateral and the nodus. 
Head and thorax black, abdomen bright red. 
Labium yellow. Labrum broadly margined with yellow, 
and the orbits anteriorly are broadly yellow. Postocular spots 
very large, rounded, connected by a line, reddish (yellowish 
in the semiadult male). 
Prothorax having its posterior margin rounded (slightly 
elevated in the male), marked with reddish (or yellow) as 
follows :—neck, two median spots (geminate), a discal one 
either side of these, a large external one on either side, and 
the posterior margin. 
Thorax with a narrow reddish (or yellow) antehumeral 
line connected anteriorly with an inner spot, and dilated pos- 
teriorly in a triangular manner; median crest very narrowly 
reddish (or yellow). Sides reddish (or yellowish), with two 
oblique black bands, whereof the upper is abbreviated. Pectus 
black. 
Legs red (yellow in the semiadult male) with black spines ; 
apex of tarsal joints and tips of claws black. 
Abdomen deep red (less intense in the semiadult male), 
marked with black as follows :—In the male there is a spot at 
the base of the first segment, a narrow posterior ring on segments 
