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Show 778 MR. E. E. AUSTEN ON A RECENT 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 Parana de Buyassu, when at rest on a leaf looks exactly like an Ichneumon of the genus Cryptus, holding its fore legs in the air and waving them about just as an Ichneumon waves its antennae. The front tarsi of this species of Calobata are white, and since all the species of Cryptus have white-banded antennas the resemblance is greatly increased. But as Ichneumons are not armed with stings, while, on the other hand, they attack larvae 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, Zenlthoptera americana, L., a small dark-winged Libellulid, was not uncommon. At Gurupa, on Feb. 22,1 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 wdngs 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 m y 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. Therephosidae) are to be communicated to tbe 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 Urubii 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 Para w7as 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 Taplnauchenius |