778 MR. B, EB. AUSTEN ON A RECINT ZooLOGICAL = [June 16, 
As has already been mentioned, the flies belonging to this genus 
have narrow bodies and long legs, while in many species the front 
tarsi are white. A medium-sized reddish Calobata (possibly new), 
which I found at the Paranda de Buyassu, when at rest on a leaf 
looks exactly like an Ichneumon of the genus Oryptus, holding its 
fore legs in the air and waving them about just as an Ichneumon 
waves its antenne. The front tarsi of this species of Calobata are 
white, and since all the species of Cryptus have white-banded 
antenne the resemblance is greatly increased. But as Ichneumons 
are not armed with stings, while, on the other hand, they attack 
larve and not perfect insects, it is difficult to see what benefit the 
fly can obtain unless the species of Cryptus are distasteful to birds. 
The third instance of protective resemblance belongs to a different 
category.. Among other Dragonflies, Zenithoptera americana, L., 
a small dark-winged Libellulid, was not uncommon. At Gurupa, 
on Feb. 22, I noticed that these insects have a habit of settling on 
the tips of dead twigs from five to ten feet from the ground, and 
drooping their wings downwards and forwards, so that they look 
exactly like bunches of dead leaves. Three or four individuals are 
usually seen on adjacent twigs, and they will remain motionless in 
this way for several minutes. I am informed by my friend 
Colonel Bingham, F.Z.S., that he has observed similar habits in the 
case of certain species of Dragonflies in India. 
Since my time was fully occupied with the Insects, I cannot say 
much about the remaining Classes of Arthropods ; nor is it 
necessary that I should do so, since these groups (Spiders, Scorpions, 
Myriopods, and Peripatus) were the special care of Mr. Pickard 
Cambridge, the results of whose study of the large Hairy Spiders 
(fam. Therephosidz) are to be communicated to the Society to-night. 
These particular Spiders, the monsters of their class, were more 
or less common at most of the localities visited by us, and Mr. 
Pickard Cambridge’s exertions were rewarded by the acquisition of 
a large series of specimens, including, I believe, representatives of 
a number of new species. On landing for the first time on the 
shores of the Para River after a slight detour rendered necessary by 
the presence of a dead bullock, attended by the inevitable Urubu 
Vulture (Cathartes atratus), the first object that met our delighted 
gaze was one of these Spiders on the stem of a palm-tree. The 
common species in the vicinity of Pard was Avicularia avicularia, 
L., of which a specimen was found in almost every palm-stump 
in a clearing to which we paid several visits. These great spiders 
rarely leave their retreat during the day, but seem fond of sitting 
at the mouths of their holes, with the tips of their legs projecting 
from beneath a protecting layer of thick web. They are very timid, 
and almost invariably dart back into their holes when approached. 
In the case of the individuals living in the palm-stumps, however, 
a lighted match dropped into the hole was found to be an excellent 
means of effecting an immediate capture. Other species live in 
leaves, or in bag-webs beneath loose pieces of bark on tree trunks, 
while in the campo at Santarem a new species of Tapinauchenius 
