189fi.] EXPEDITION ON THE LOWEH AMAZON. 777 



For some reason we did not meet with a single specimen of 

 the v\ell-known "fire-flies" belonging to the genus Pyrophorus, 

 either on the Para Biver or the Amazon itself, although I believe 

 they were found by Mr. Pickard Cambridge in the forest near 

 Sanlarem. Fire-flies of the family Lampyridie, however, of wliich 

 our common English Glow-worm (Lampyris noctiluca, L.) is a 

 well-known example, visited the ship in numbers by night as we 

 ])roceeded up the river. They were especially conspicuous in the 

 Monte Alegre furo on the night of Feb. 17, flashing out like 

 spaiks against ihe dark background of trees, and scintillating at 

 intervals as tlioy occasionally floated over our launch. Most of 

 (ho species collected belong to the genus Aspidosoma, including 

 among others A. maculaium, Beg., and A. heaperum, L. In the 

 campo at Santarem on Jan. 29 we took a handsome species of Dung- 

 Beetle {Phanceus mimcts, L.), the passage of some cattle along the 

 sandy road affording us an opportunity of observing the wonderful 

 rapidity with which these beetles appear on the scene and bury 

 thorasRlves within a few minutes of the requisite attraction being 

 provided for them. 



The only other insects to which I need now refer are the 

 Dragonflies {Neuroptera Odonata). As micfbt naturally be expected 

 in such a land of waters this Order was perhaps more in evidence 

 than any other, and was particularly well represented in indi- 

 viduals, although the actual number of species met with was not 

 very great. Though some of the species, again, were exceedingly 

 beautiful in colour when alive, in size they in no way surpassed 

 our British forms. The remarkable ease with \i hieh a Dragonfly, 

 even when coming straight towards his would-be captor, contrives 

 to elude the net is well known ; for some reason I invariably 

 found the rarer species the most difficult to catch ; the common 

 ones gave little trouble. I frequently had the opportunity of 

 observing how a Dragonfly drinks ; hovering motionless a foot or 

 two above the water he suddenly makes a sharp dart forwards at 

 it, striking it with his mouth and the underside of the thorax, and 

 at once withdrawing to bis previous position ; the process is 

 repeated several times. 



Mimicry. — Three cases of apparently genuine mimicry among 

 Insects, which came under my notice, seem worthy of mention. 

 The first, which has probably not been recorded before, is that 

 of a small Clearwing Moth (fam. Sesiidfe), which is an almost 

 exact replica of a Wasp (Polybia plitliisica, F.), of which I obtained 

 several specimens at Manaos and the Parana de Buyassu. In size 

 and general coloration the two insects are the same, and the pattern 

 of orange and black stripes on the thorax of the Wasp is copied so 

 closely by the Moth that at a little distance it would puzzle even 

 an entomologist to distinguish the two species. Unfortunately, I 

 only obtained a single specimen of the Clearwing; it is not repre- 

 sented in the Museum collection, and is very probably new. 



The second case of apparent mimicry, to which I would draw 

 attention, is that of the Dipterous genus Cahhata, alluded to above. 



