r9t5.| F. H. GRAVELY: Indian Mygalomorph S piders. 285 
Genus Chilobrachys, Karsch. 
Simon’s definition of this genus applies only to those species 
in which the stridulating organs approach or attain their highest 
degree of specialization. To the simpler forms it is inapplicable. 
This is especially so in the case of C. assamensis and C. fumosus, 
species which resemble Selenocosmia himalayana in the structure 
of the parts of the stridulating organs situated on the chelicerae, 
and approach it more closely than do any other species of Chilo- 
brachys known to me, in the structure of the parts of these organs 
situated on the palps. The stridulating organ of C. assamensis has 
already been figured (Gravely, 1915, pl. xxx1, fig. 5). 
C. assamensts and C. fumosus are closely allied to one another. 
C. fumosus appears invariably to attain a much greater size than 
C. assamensis. but in view of the great range in size shown by 
S. himalayana (see previous page) and by C. hardwickii (see fol- 
lowing page) this, the only difference known to me in females, 
cannot be regarded as an altogether satisfactory character. 
The palpal organs of males of the two species are remark- 
ably alike in their general features, but the style is longer and 
more abruptly spatulate at the end in C. fumosus than in C. assam- 
ensis. The latter species is represented in our collection by 
cotypes of both sexes from Sibsagar in Assam. ‘The former is 
represented by two males from Kurseong, on one of which (that 
collected by Dr. Annandale) Hirst’s description of this sex (1909, 
pp. 386-7—the only one yet published) was based. Females and 
young, which must provisionally be referred to this species, are 
represented in our collection by specimens from Chitlong in Nepal ; 
Singla, 1500 ft., Darjeeling, Sureil and Kalimpong in the Darjeeling 
District ; the Assam-Bhutan Frontier of Mangaldai District; and 
Burroi at the base of the Dafla Hills. It remains to be seen, 
however, whether the males from all these localities belong to a 
single species. If not, as the type is a female labelled ‘‘ North 
India’, the name C. fumosus should be kept for the Kurseong 
(Darjeeling District) form. The arrangement of the spines on 
the chelicerae in parallel rows is more or less clearly marked in 
certain specimens of this and other species; it cannot be regarded 
as a good specific character. 
In Chilobrachys assamensis and fumosus the largest bacilli on 
the palps are situated in the distal half of the ventral row, and 
the stridulating processes of the chelicerae are slender and spini- 
form as in Selenocosmia. In all other species which I have seen the | 
largest bacilli are proximal, and the projections against which 
they work are short and denticuliform. In a species from the 
Malay Peninsula, however, the former are practically median, 
though the dorsal spines are concentrated a little on the distal side 
of them. It is possible that Chilobrachys assamensis and fumosus 
have originated independently of the rest of the genus, in which 
case the former might be made the type of a new genus containing 
the latter and perhaps also Selenocosmia himalayana, But the 
