14 LEC4S xVND AVING8. 



in the antero-postei'ior direction, with a vuhiform median groove 

 (the anus) running from the anterior margin to beyond the middle. 

 Ventral surface of the sixth segment in the male, immediately in 

 front of the hypopygium, exhibiting on each side of the middle 

 line a chitinised plate, roughly oval in shape and bearing a patch 

 of close-set, erect or recurved, minute black hairs ; * ventral 

 surface of the remainder of the sixth segment and that of the 

 remaining segments except the first in the male, and of all the 

 segments except the first in the female, membranous. 



Legx simple, rather long, claws longer and pulvilli somewhat 

 larger in the male than in the female. Front femora with a row 

 of bristle-like hairs above and below, and (except in the case of 

 G. m,orsitans f ) on the posterior surface with a median row of 

 minute black spines. Middle and posterior femora with a row 

 of bristle-like hairs on the basal half of the anterior surface, near 

 the upper margin, and with a shorter row of similar haix's, or 

 short bristles as the case may be, at the base beneath. Middle 

 femora with a solitary bristle, usually conspicuous in the larger 

 species, on the upper side near the tip. Tibiae with a well-marked 

 ridge, edged with a row of closelj'-set minute black spines, 

 running down the outer surface, so that they, especially the 

 front and hind pair, usually have the appearance of being 

 somewhat flattened from side to side ; the middle tibiae have a 

 second row of still more minute spines in advance of that just 

 mentioned, the space between, owing to the presence of the 

 I'idge, having the appearance of being excavated. Tibiae also 

 with a row of short fine hairs or bristle-like hairs running down 

 the outer side, and sometimes with one or two short bristles close 

 to the apex on that side, otherwise, with the exception of the 

 usual apical spines, entirely devoid of isolated bristles or bristle- 

 like hairs. On the three basal joints of the front and middle 

 tarsi three rows of minute black spines similar to those on the 

 tibiae ; on the basal joints of the hind tarsi they are less distinct, 

 but apparently two rows are present. 



Wings with an ahsolutehj unique venation (see Fig. 7), which, 

 apart from all other characters, will at once serve to distinguish 

 a specimen of the genus. The most striking peculiarity is the 



* These plates, the function of which obviously is to assist in holding 

 the female during copulation, may be termed the hectors (Greek tKTwp, 

 holding fast) ; they sometimes furnish useful characters for the distinction 

 of species. 



t In the case of G. longipennis, too, the row appears to be broken up 

 into a double line and is consequently barely distinguishable. 



