Chap. I. AQUATIC INSECTS. 31 



about half a dozen kinds, are blown across, and become 

 perfect pests to the town's people for two or three nights. 

 swarming about the lights in every chamber. They 

 get under one's clothing, or down one's back, and pass 

 from the oil-lamp on to the furniture, books, and papers, 

 smearing everything they touch. The open shops facing 

 the beach become filled with them, and customers have 

 to make a dash in and out through the showers that 

 fall about the large brass lamps over the counter, when 

 they want to make a purchase. The species are cer- 

 tainly not indigenous to the eastern side of the river ; 

 the hosts soon disappear ; those which cannot get back 

 must perish helplessly, for the soil, vegetation, and 

 climate of the Santarem side are ill suited to the 

 inhabitants of the opposite shore. 



The pools I have mentioned were tenanted by a 

 considerable variety of insects. * I found also a very 

 large number, chiefly of carnivorous land-beetles under 

 the pebbles and rejectamenta along the edge of the 

 water during my many rambles. I was much struck 

 with the similarity of the Dragon-flies (whose early 

 states are passed in the water) to those of Britain. A 

 species of Libellula with pointed tail, which darted 

 about over the bushes near the ponds, is very closely 



* The water-beetles found in the pools belonged to seventeen genera, 

 thirteen of which are European . Those European genera which form the 

 greater part of the pond population in Coleoptera in northern latitudes, 

 are quite absent iu the Amazons region : these are, Haliplus, Cnemi- 

 dotus, Pelobius, Noterus, Ilybius, Agabus, Colymbetes, Dyticus, and 

 Acilius : Hydropori, also, are very rare. The most common species 

 belong to the genera Hydracanthus, Copelatus, Cybister, Tropisternus, 

 and Berosus, three of which are unknown in Europe. 



