1895. 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



131 



Fig. 8. 



10 as wide or wider than base of 4. In the young males the colors are : 



1 light olive green, dorsum with a dark brown spot each side; 2 similar, 

 dorsal spots, darker in front of and widest at the black, transverse 

 median carina; 3 and 4 light brown, dorsum with a darker stripe each 

 side reaching the apex but not the base; 5 and 6 blackish, with a light 

 brown spot on each side of dorsum at middle; 7-10 black dorsally; 1-4 

 light brown ventrally; 4-7 blackish ventrally, an elongate brown spot 

 on the middle, each sideof the venter; with age, the abdomen becomes 

 more and more lu'uinose. 



Superior appendages about twice as long as 10, yellow in young, 

 darker and even black in older males; viewed from above, each append- 

 age is straight, dilated on the inner side before the apex, which is 

 acute; viewed from the side, each is directed downward (but the apex 

 slightly upward), with 8 or 9 denticles on the underside. Inferior 

 appendage about a third shorter, luteous; viewed from the side, 

 it forms a dorsally 

 concave curve from 

 base to apex, end- 

 ing in the usual two 

 denticles, which do 

 not reach as far as 

 the last denticle of 

 the superiors (in 

 only one male do 

 they reach farther) ; viewed from below, the appendage is broad, trian- 

 gular; apex black, truncated, slightly emarginate. 



Genitalia of 2 prominent. Anterior lamina much as in 0. bninnea, 

 with sides rounded to the apex, which is truncated and (usually) slightly 

 emarginate. Hamule with apex bifid, branches parallel, of equal 

 length;^ internal branch rather slender, apex slightly hooked and 

 directed outward; external branch twice as thick, apex rounded; geni- 

 tal lobe as pronounced as in 0. ccerulescens, broad, apex rounded; the 

 internal hamular branch projects slightly farther than the anterior 

 lamina or the genital lobe. 



Wings hyaline, with a slight smoky tinge, especially near the apex. 

 Eeticulation dark brown, costa yellowish anteriorly as far as the 

 pterostigma. Hind wings with a small rufescent basal spot reaching 

 from the submedian to the apex of the membranule and outward for 

 one or two cells. Pterostigma dark brown, four times as long as broad. 

 Membranule blackish brown, whitish at extreme base. Front wings 

 with 12-16 antecubitals, 8-12 postcubitals, one hypertrigonal; triangle 

 with one cross vein, internal triangle of three cells, three rows of post- 

 triangular cells. Hind wings with 9-13 antecubitals, 10-13 postcubitals, 

 no hypertrigonals, sectors of the triangle united or a little separated at 



Fig.' 



(7) Side view oflast thr 



OKTHETRUM BRACHIALE. 



ibdominul segments, female; (8) Side 



' Owing to the oblique position of the hamnle, however, the internal branch 

 appears more prominent than the external. 



