50 



tera) for about two-thirds of the length of the corium, after 

 which the subcostal continues alone to the apical margin of the 

 cerium, meeting the costal there ; the radial sector deflects to 

 meet at an angle a fork of the median, the two continuing to 

 the apical margin of the membrane, the median continuing also, 

 rather deflectedly, to the apical margin of the corium. This is 

 the case in such typical forms as capsiformis, but the relations 

 of the veins are more obscured in lusciosiis, &c. 



There are several little points which cannot be settled without 

 recourse to freshly emerged specimens, but for systematic pur- 

 poses, it is sufficient to say that a large area is formed in the 

 basal middle of the membrane which is traversed longitudinally 

 by two submedian veins, which in some species are simple, in 

 others shortly forked. This venation, however, is not of a posi- 

 tive specific value, as variations occur even in the two tegmina 

 of the same specimen. 



In the Ncsotyphlias series, at least in R. lusciosus, the vena- 

 tion is very similar, except that the tegmen is much more coria- 

 ceous (though the brachypterous form of R. blackburni ap- 

 proaches in that respect), and the clavus is not separated, but 

 the length of the main veins is variable, the membrane is very 

 oblique and much shortened. In R. kaolunani and its allies, the 

 tegmina are still more reduced. 



It is not possible to interpret the wing from that of the mature 

 adult. There are two main, subhorizontal veins (the "primary" 

 and the ''subtended'") ; these do not reach the margin, but are 

 joined about their middle by the "connecting" vein, from the 

 lower half of which arises the hamus {h) ; the claval commissure 

 is accompanied by a vein from which springs an arched one. 

 The uppermost vein is possibly the subcostal (joined basally to 

 the radial), and the next is possibly the median, the hamus rep- 

 resenting the radial sector. (PI. I, f. ii). 



The venation is a little reduced in the brachypterous form 

 of R. blackburni and much more in R. nesiotcs (PI. i, f. 12), 

 while the wing is almost obsolete in the Nesotyphlias group and 

 has no appreciable venation. 



The males are much slenderer than the females, in which the 

 abdomen is more or less widened laterally in the middle. The 

 ovipositor is very conspicuous. In the males, the pygophor is 

 ornamented by a hook on each side (PI. i, fs. 1-4), which is arti- 

 culated close to the apical margin, and in repose lies fairly flat 

 against the body, with the acute end pointing forwards, but can 

 be turned in a sort of socket so that this end can point in the 

 opposite direction. These hooks consist of two parts, which, 

 however, are all of one piece, the "handle" and the "blade." 



