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 in the Amazons region : these are, Haliplus, Cnemi- 
dotus, Pelobius, Noterus, Ilybius, Agabus, Colyrabetes, Dyticus, and 
Acilius : Hydropori, also, are very rare. The most comm^on species 
belong to the genera Hydracanthus, Copelatus, Cybister, Tropisternus, 
and Berosus, three of which are unknown in Europe. 
