1915.] F.H. GraveLy: Indian Mygalomorph Spiders. 261 
binations of the other characters used by Simon in his generic 
definitions. 
I have therefore fallen back on Simon's earlier revision of 
the group (Vol. I, pp. 90-92), which, when Acanthodon has been 
merged in /diops, takes in all these forms conveniently. 
Genus Heligmomerus, Simon. 
Represented by one female, caught in the Royal Botanical 
Gardens at Sibpur near Calcutta, where it may easily have been 
introduced among plants from some other place. Its burrow, a 
short silk-lined tube, closed externally by a trap-door, is also in 
our collection. 
Genus Idiops, Perty. 
Represented by a female from Bellary in South India, and by 
a male whose characters seem sufficiently well defined to permit 
of its description here as a new species. 
Idiops biharicus, n. sp. o@. 
(Pl. xv, figs. 1 a-b). 
Locality.—Sahibgunge in Bihar. 
Dimensions.—Carapace 6:0 X 5°2 mm.; sternum 3:0 X 2°8 
mm.; legs in the order 1, 4, 2, 3. In the first legs the femur is 
fully, and the combined tarsus and metatarsus are scarcely, as 
long as the carapace. The patella and tibia combined are a little 
longer than either. The tibia and metatarsus of the second legs 
are about equal to the patella and tibia of the first in length, 
but are much slenderer. The tibia of the third leg on each side 
is nearly three times as long as wide; the femur and patella of 
these legs are together scarcely as long as the carapace, and are 
about equal to the femur alone of the fourth legs. 
Colour.—Carapace plum-coloured; appendages dark reddish 
“above, paler beneath especially basally ; sternum and lower surface 
of abdomen also pale, almost ochraceous; upper surface of al)do- 
men dull brown. 
Structure.—The carapace is ovate, slightly narrower behind 
than in front, with the posterior margin short and faintly concave 
in the middle line. The anterior lateral eyes are situated close 
together on a prominent tubercle close to the anterior margin. The 
remaining eyes are situated in a compact group: of these the ante- 
tior medians are almost in contact, and are the largest ; the posterior 
medians are separated by a distance about equal to a diameter of 
one of the anterior medians, and are the smallest; both are almost 
in contact with the posterior laterals, whose long diameter is about 
equal to that of an anterior median, and whose other diameter is 
about equal to that of a posterior median. The fovea is large 
and very deeply impressed in the form of a procurved semicircle. 
