44 
Annals of the Transvaal Museum 
terminal fang of the lower jaw not keeled on the outer side, or only 
weakly so, and not greatly elongated in the adult male, the distance 
from the tip of the fang to the apex of the first tooth being usually ij 
times, or less, or at any rate not greater than if times the distance 
between the apices of the two large teeth : mesial surface of both upper 
and lower jaw usually with fairly strong development of feather bristles. 
In the male, the tibia of the palp is scopulate inferiorly over some portion 
of its length: upper margin of basal enlargement of flagellum blunt or 
sharp, but not greatly compressed into a thin high keel (except perhaps 
in darlingi ) : no keel on the mesial surface of the fang just in front of the 
anterior bend of the flagellum. Posterior median angles of the two halves 
of the first abdominal sternite in the adult female either rounded or 
rectangular, never produced into narrow lobes. Posterior legs usually 
with sparsely disposed long hairs (occasionally as in sericea with nume- 
rous very long ones), never forming a distinct mane in either sex. (Species 
mostly nocturnal in habit and plainly coloured, being uniformly yellow 
or brown: only occasionally striped with black, or with strongly con- 
trasting colours on the abdomen.) 
A. Flagellum slightly produced anteriorly, the anterior bend 
situated fairly far forwards, over the first or second tooth: shaft 
long and subcylindrical over the greater portion of its length and 
with a projecting tooth near to the apex, or distinctly bifurcated 
distally. 
1. Flagellum very long, reaching backwards as far as the ocular tubercle- 
or a little further, strongly sinuate not far from the apex and just proximal 
to its lateral tooth which is short and sharp : the shaft of the flagellum is low 
lying, being only just above the basal enlargement anteriorly. 
5. lethalis typicus Koch. 
2. Similar thereto, but shaft of flagellum straight, not sinuate, the 
shorter apical branch ending bluntly and its surface minutely serrulated. 
5. lethalis rectus var. nov. 
3. Flagellum reaching backwards beyond the middle of the mandible but 
terminating some distance in- front of the eye tubercle, only lightly sinuate 
between the apex and the short sharp lateral tooth; the apex laterally com- 
pressed and dilated above into a knife-like edge: anteriorly, the recurrent 
portion almost touches the basal enlargement. 5. venosa Purcell. 
4. Flagellum reaching backwards beyond the middle of the mandible but 
not reaching the head-plate, terminating in a short sharp subulate apex at 
the base of which a fine straight pallid bristle-like process springs from the 
upper edge and extends backwards beyond the apex: proximally the shaft 
lies close to the basal enlargement, which is well elevated: anterior bend of 
flagellum situated behind the level of the first tooth and nearly over the 
second. Lower jaw with two or three small intermediate teeth. Dorsal surfaces 
of body, head-plate, and appendages strongly infuscated throughout in both 
sexes. 5. fusca C. L. Koch. 
5. Similar to fusca, but the spine-like process near the apex of the flagellum 
much shorter, not extending as far as the apex: anterior bend of flagellum 
situated almost immediately over the first tooth. Lower jaw with only one 
intermediate tooth. Dorsal surfaces somewhat infuscated. 5. toppini Hirst. 
