128 THE VICTORIAN NATURALIST. 



dry season is the highest temperature, which does not exceed 

 95 deg. Fahr., and in some of those months there is no rain. In 

 the rainy season as much as 20 inches fall in one month, 5 inches 

 having been registered in 24 hours. The lowest temperature is 

 68 or 70 deg. F. The death rate for Europeans, chiefly through 

 malaria and other climatic causes, varies from 5 to 25 per cent, 

 of the population. 



ON THE FERTILIZATION OF PHANEROGAMS. 

 II. — Dispersion of Pollen by Insects. 

 By G. Weindorfer. 

 {Read before the Field Naturalists' Club of Victoria, 9th December, 1902.) 

 In my previous paper I spoke of the fertilization of flowers 

 through the agency of the wind. I purpose now giving some 

 account of the part insects play in effecting the same object. 



Now, the male and female cells, or the organs which produce 

 them, arise either close to one another or at a distance on the 

 same plant, or they may arise on different individuals of the same 

 species ; the sexual cells of the same species of plant may thus, 

 according to their origin, be more or less closely related, behaving 

 towards one another as sister cells, as cousins, or as their grand- 

 children and great-grandchildren, and so on. 



When in one and the same flower, the organs in which the 

 pollen and those in which the ovules are developed stand closely 

 side by side ,; it might be thought, therefore, that the pollen would 

 be certain to reach the adjoining stigma, but this opinion is not 

 confirmed by experience. It has been demonstrated that it is of 

 advantage to the plant that the pollen of one flower should reach 

 the stigma of another — indeed, of a flower of quite another plant, 

 often some distance- away. The wonderful and extremely 

 complicated contrivances which are met with for the attainment 

 of the dispersion of the pollen by means of insects will be partly 

 considered in to-night's paper. 



Contemporaneously with the opening of the earliest spring 

 flowers occurs the escape of the first pioneer butterflies from 

 their chrysalides, and the same sunny day which rouses hive 

 bees and humble bees from their winter sleep sees the flowers 

 offering their pollen and honey to the world at large. Many 

 flowers which open early in the morning are visited only by par- 

 ticular insects which leave their nocturnal haunts at the same 

 hour. Other flowers do not open till sunset, when day-flying 

 insects are already gone to rest and they are visited by others, 

 which have remained throughout the day concealed in shady 

 nooks and commence their rambling when dusk sets in. 



Now, first of all the question arises : what is it that induces 



