44 NATURAL SCIENCE. Jan.. 



swarms of bees. By far the greater number of insects are nocturnal 

 in their habits, and, as might be expected, white flowers are very 

 plentiful. This makes observation so very difficult, as few of the 

 insects can be seen at work. Now and again, however, a belated 

 moth may be seen taking a last sip in the early morning, but such 

 cases are rare. 



After the contrivances for fertilisation, those by which fruits are 

 protected and disseminated are most interesting. Nearly all those of 

 our tables have thick skins, often charged with acrid secretions. 

 These have acted so well that fruit-eating flies and wasps are almost 

 wanting in Guiana. Birds, however, peel some of them, while bats 

 succeed in utilising all except perhaps those of the orange family. 

 In the forest the variety of pods, capsules, berries, and other seed- 

 vessels is almost overwhelming. Perhaps the most useful develop- 

 ments which are common to almost all are those by means of which 

 they float and are carried long distances by water. This object is gene- 

 rally attained by means of spongy pericarps, but many other devices 

 are common, all helping to spread the seeds over very wide areas. 

 In the Lecythidese we have apparently protective contrivances against 

 monkeys. The Brazil nut [Bevtholettia) has a hard, woody capsule 

 without an opening, which falls to the ground entire. In the genus 

 Lecythis there is a cover which falls off when the nuts are ripe, and 

 allows them to scatter in every direction. It is probable that 

 monkeys try to get at these, and by loosening the covers let them fall 

 out without being able to secure more than one or two. The 

 cannon-ball tree (Coiiroupita) has a softer covering, but this smells so 

 very disagreeably that neither monkeys nor rodents will touch it. 

 Other natural orders repel animals in different ways. The short 

 brittle hairs on the cowhage [Mucnna) pods would undoubtedly prove 

 more than distasteful to bird or beast, as would also the prickles on 

 the seed-vessel of the Allamanda. Sometimes the seed itself is 

 protected, while the covering or pulp surrounding it is obviously 

 intended to attract. In such cases birds assist the tree by scattering 

 its seeds, and are therefore invited. In the bignonias, so 

 common along the banks of the rivers, the seed has a delicate 

 membranous expansion, on which it floats in the air like a butterfly. 

 Other climbers have feathery appendages, while the stately Triplaris 

 lets its seeds sail down like shuttlecocks. 



Fibrous coverings to the stems are common among the tropical 

 weeds. Exposed as these are to vicissitudes unknown in the forest, 

 they have developed contrivances distinct from those of the trees. 

 The most common mode of overcoming the difficulty of a dry season 

 when the roadsides can no longer supply sufficient moisture is the 

 faculty of ripening seeds before this takes place. In the forest, 

 every plant is a perennial, but annuals are common on the dry 

 savannahs, as well as on waste land in the towns and villages. Many 

 weeds are not only repellent to man, but even to domestic animals 



