So Records of the Indian Museum. [VoL. XII, 
The genera characterized by the specialization of the tibial 
apophyses of males are three in number—Labochirus, Hypoctonus 
and Typopeltis. 
The distribution of the genus Labochirus, as already pointed out 
(above, p. 61), suggests that this genus, which contains almost all 
the most primitive representatives of the keelless group in the Indo- 
Australian area, once had a more continuously wide distribution 
than is at present the case. Its most highly specialized species ap- 
pear to be confined to Burma, in and around which country and 
nowhere else the remaining Indo-Australian genus of the keelless 
group—Hypoctonus—is found. The more primitive species of this 
genus closely resemble those of the last, proving a common origin 
for the two; but the proportion of highly specialized species is 
much greater. I have already alluded to the concentration of this 
highly specialized genus in Burma as evidence that the conditions 
found among the secluded valleys of this country have acted as a 
stimulus to evolution in the same sort of way as the conditions 
found among the islands of the East Indian Archipelago, a con- 
clusion which finds support in other groups (see Gravely, 1915a, 
p. 416). 
The genus Hypoctonus appears to be dominant over the whole 
of Burma, and its range extends beyond the Siamese frontier 
almost to Raheng in the Me Ping Valley, an immature specimen 
having been sent to us by Mr. C. S. Barton from laterite jungle 
in the forest surrounding the Metaw River, a river which joins 
the Me Ping from the west close to Raheng. From open ground 
in this forest Mr. Barton has also sent us an immature specimen of 
the genus Thelyphonus, a genus which appears to be widely dis- 
tributed in Siam and Indo-China. It is difficult to determine, 
from the evidence at present available, whether Thelyphonus or 
Typopeltis is the dominant genus of the two last named countries, 
or whether both are equally common. 
Typopeltis extends northwards to Japan and Siberia. It 
resembles the keelless genera already dealt with in having the 
tibial apophyses of males strongly modified, though perhaps in 
general a little less strongly. In addition, however, the tarsi of 
the antenniform legs of females—though always long—are often 
somewhat modified, a thing which is unknown in the keelless 
genera. It is impossible in the present state of our knowledge to 
locate the evolutionary centre of this genus, but it is noteworthy 
that the only species in which the antenniform legs of the female 
are known to be unmodified is Typopeltis amurensis' from Siberia 
on the periphery of the range of the genus. 
Omitting the genus Mimoscorpius (from the Philippines), of 
which scarcely anything is known, the keeled genera with unmodi- 


! The type specimen is a female from Siberia. Kraepelin (1897, p. 13) 
identifies with this amale from Canton. In view of the limited range of most spe- 
cies of Thelyphonidae the correctness of this identification can scarcely be con- 
sidered certain. Unfortunately nothing is known of the sex of the Indo-Chinese 
specimens in the Paris Museum. 
