184 THE ZOOLOGIST. 



not usually exist in the heart of great tropical forests. Owing 

 to loss of water by transpiration, draining of the soil by roots, 

 and other causes, tropical forests and permanent marshes are to 

 a large extent mutually exclusive. The same thing applies, 

 though less markedly, to many temperate forests. If then there 

 are no permanent marshes over large areas of tropical forest, 

 how does this affect all the animals which, either throughout 

 their whole lives or in certain stages of them, are dwellers in 

 marshes and pools ? Are such creatures absent from the forests ? 

 On the contrary, many amphibious and aquatic creatures exist 

 in such forests, and they are able to do so because the place of 

 terrestrial pools and marshes is taken by accumulations of water in 

 reservoir-plants. In some of these the water collects only at 

 times, in others it is permanent. But in most parts of the 

 world, and more particularly of the tropics, great forests contain 

 reservoir-plants of some kind. It is not attempted here to give 

 an exhaustive list, but let us review briefly the principal kinds 

 and the fauna which has been found to inhabit them. 



(A.) First there are certain plants which hold water only 

 accidentally, and then only for a time. The most important 

 examples are the bamboos, which often hold water in the ends 

 of broken stems, in the spaces between sheathing leaf-bases and 

 stems, &c. Such accumulations of water have been found in 

 Malaysia to contain larvae of Culicid and Chironomid flies, and 

 of Dragonflies, and in Central America to contain lame of 

 Mosquitoes of the Megarhine group. 



(B.) True reservoir-plants : these are plants which quite nor- 

 mally possess water- or detritus-holding receptacles. 



First may be mentioned the order Musacece. Musa, the 

 banana, holds water between the stalks of its great leaves, and 

 in the New World tropics Heliconia holds water in its gaudily- 

 coloured, cup-like floral bracts. These plants are said only to 

 hold water temporarily, but in both have been found certain 

 aquatic insect larvae, especially those of Mosquitoes. 



Next, one may refer to the well-known pitcher-plants, 

 Nepenthes, of the Old World tropics. In these the midrib is 

 prolonged beyond the lamina of the leaf, and bears at its end the 

 pitcher. Insects attracted by the honey-glands of the pitcher 

 are drowned in the water which it contains, and the plant absorbs 



