164 FUNCTION OF COLOUB AND SMELL IN FUNGI. 



while the fungi sought after by all six would be avoided by- 

 other birds and quadrupeds. Probably also when the subject 

 has been more thoroughly worked out, the most interesting 

 revelations will be forthcoming from the relationship between 

 fungi and birds. In this respect I have been much struck by 

 what has come under my own observation. Whenever I have 

 seen a bird holding high carnival over a fungus, I have carefully 

 gathered up the fragments for examination, and in every 

 instance I have found buried in the tissues huge larval forms of 

 insect life. To the questions : — How did the birds learn of such 

 a rich meal hidden deep in the living vegetable tissue? and, 

 Why did they attack those fungi only in which the larval forms 

 had attained maturity? — no better solution has yet been 

 forthcoming than that they were guided by colour and smell. 



From the time of their first appearance, to their ultimate 

 decay, most fungi develop an increasingly powerful odour. In 

 their early stage some have a slight smell by day, and would 

 therefore be attractive to diurnal insects. Others give forth 

 their odour at night-time only, in which case strictly nocturnal 

 insects, such as moths, would be their only visitors. In the 

 young stage I have failed to find animal life of any kind in their 

 tissues, but microscopic examination has revealed minute 

 punctures of the surfaces in which tiny eggs have been snugly 

 deposited. It is important to note also that at this early stage I 

 have not known the fungi to be attacked by bird or quadruped. 

 When the spores of the fungi are ripe and ready for dissemina- 

 tion, the plant acquires a more pronounced smell, varying, 

 according to the species, from putrid fish and ordinary carrion 

 to sweet-smelling fruit and flowers. Examination has proved 

 that at this stage also the maggots in the putrifying mass have 

 attained their full size. Attracted by the odour, which has 

 doubtless a powerful ally in colour, now come the birds. Long 

 experience has taught them to connect the particular smell with 

 a meal, and it is, as I suppose, while devouring the living 

 contents of the fungi, that they also swaUow large quantities of 

 spores. And for this latter purpose, in the main, it would seem 

 that the complex but interesting series of mutations and 

 correlations has been evolved. 



