66 INSECTS ABROAD. 



water when covered with ice as when warmed by the hot sun- 

 beams of July and August. Yet, though they are thus hardy, 

 they have a manifest preference for warmth ; and in any place 

 which is kept exceptionally warm, there the Water Beetles and 

 their larvai flourish mightily. 



Close by my house there is a little pond of this character. 

 No wind but the soft southern breeze blows over it, and 

 throughout the whole of the year every sunbeam that passes 

 the barrier of the clouds falls on the surface of the pond. Con- 

 sequently it absolutely swarms with aquatic Beetles, which can 

 scarcely swim or dive through its waters without jostling each 

 other; and if an ordinary insect net be simply drawn once 

 through the water, it comes up laden with a large mass of 

 kicking and struggling Water Beetles. 



Such being the effect of warm temperature upon the aquatic 

 Beetles at home, it is but natural to infer that the ponds and 

 streams of tropical climates, which are much warmer than those 

 of our own country, would furnish a vast number of new species 

 to the insect-hunter. This, however, is not the case, for the 

 whole of the tropical countries put together scarcely exceed our 

 tiny island in the number, size, and beauty of their Water 

 Beetles. Our common Great Water Beetle {Byticus marginalis) 

 is about as large and just as handsome as the finest of its tropical 

 relatives, and among the whole of foreign Water Beetles there 

 are very few that are in any way distingniished from our own 

 insects. 



Mr. Bates, in his " Naturalist on the Amazons," makes some 

 remarks on this subject. While at Para he was visiting a lake 

 for the express purpose of collecting specimens of Natural 

 History, but was much disappointed in one respect. " I was 

 surprised to find no Coleopterous insects on the aquatic plants. 

 The situation appeared to be as favourable for them as possibly 

 could be. In England, such a richly-mantled pool would have 

 yielded an abundance of Donaciae, Chrysomelae, Cassidae, and 

 other Beetles — here I could not find a single specimen. Neither 

 could I find any Water Beetles ; the only exception was a species 

 of Gyrinus, about the same size as Gijrimis natator, the little 

 shining AVhirligig Beetle of Europe, wliich was seen in small 

 groups in shady corners, spinning round on the surface of the 

 J water precisely as its congener does in England." 



