738 MR, F. 0, PICKARD CAMBRIDGE ON [June 16, 
remote from margin. Labiwm longer than broad, its apex studded 
across entirely with cuspules. Cowa of pedipalp more than twice 
its breadth; anterior distal angle produced ; anterior basal angle 
studded with cuspules, more scattered and fewer towards disc. 
Legs spinose ; fourth pair longest. Tarsi and almost the whole 
of protarsi i. and ii. thickly scopulate; of iii. tarsus and half 
protarsus, of iv. distal end, of protarsus slightly, and tarsus, scopu- 
late. Femur iv. with velvet pad on inner side. Tarsal claws 2; 
inner claw with 7, outer with 3 denticles, of first pair of legs. 
Spinners 4; posterior pair a little less in length than tibia i. 
So far as I am aware, the female of this magnificent Spider has 
never been fully described, and the specimen taken is the first of 
this sex which has come into the possession of the British Museum 
of Natural History. A. geniculata is apparently not a rare Spider 
in the Amazonian forest. One female was found by Mr. Austen 
in a hollow tree at Breves, but we were unable to secure it. I 
saw, also, more than one far down in the burrows of the Termites, 
underground, where it was useless to attempt a capture. The 
young ones to the number of a hundred or more crowded the 
entrance to one of these dens, running about over a broad thin 
sheet of webbing. The specimen described was, however, taken 
by myself from the hollow branch of a tree which had fallen in 
the forest near Santarem, the only one I was able to secure. 
Its presence was first detected by the slight white web spun 
over the end of the short decayed hollow stump, while far down 
within could be seen the pale banded legs of the spider. Fortu- 
nately—whether it is always the case or not I cannot say—-there 
was also a bolt-hole, so that, after rattling with a stick down the 
hollow, out burst the spider with a strange rustle and pattering 
of its padded feet. Had it not {been for the noise, I should 
probably not have noticed it, for I never suspected an exit at the 
other end. 
With gloved hand in front and large prune-jar held open behind 
her, she stopped, but made no attempt to attack or bite at the 
obstacle in front. But now, when pressed, with lightning speed 
she whisked off a small cloud of fine down from the back of the 
abdomen on the upperside with the claws of the fourth pair of 
legs. Pressing her in front, she went backwards into the jar, and 
at once was secured. Mr. Bates mentions the poisonous character 
of the hairs of these great Spiders, he himself having suffered from 
them; and one has often observed a bare patch on the upperside 
of the abdomen, at its apex, of many of them, whence the fine 
pubescence has been apparently rubbed off. Putting these two 
links together, and connecting them with the action which I 
witnessed, I am convinced myself—though I should need far 
more proof before I would definitely assert that such was really 
the case—that the spider whisks off these fine hairs in order to 
protect itself. It is true that, though I caught upwards of 150 
large Spiders, I never saw one, except the above, act in this way, 
