THE INSTINCTll'E BEHAJ'IOR OF ANTS. 5 2 3 



universal. Here, too, the analogy of the colony to a Metazoon is 

 apparent, for in the latter we also find that growth, ontogeny and repro- 

 duction are very rigidly determined as compared with the activities 

 that bring the organism into relation with its multiform and changing 

 environment. 



The castes have often been cited as fine examples of the correlation 

 of instinct and structure, but it is only recently that we have come to 

 feel the full force of this assertion. As I have discussed this subject 

 at some length in Chapter VII, I may here confine myself to a few 

 remarks. The male and female ant present an extraordinary contrast 

 in the development of their instincts ; the male, though possessing very 

 highly developed eyes and antennae, having such abortive instincts that 

 he scarcely ranks above many lowly organized, solitary insects, whereas 

 most female ants may be said to be richly endowed with all the instincts 

 of their respective species. For this reason, and also because the queen 

 ant, while forming her colony leads a solitary life and is not discon- 

 certed by being kept in confinement, she is an extremely favorable 

 object for the study of instinct. Her activities, as an individual, are 

 so methodical that they strike the observer, who first witnesses them, 

 as a beautiful example of the catenary or compound reflex. Beginning 

 with deflation, which seems to be the necessary initiatory stimulus, 

 she goes through a regular routine, excavating a small cell in the earth, 

 closing its opening, laying eggs, feeding the larval workers with her 

 own secretions, guarding them, burying them when mature till they 

 have spun their cocoons, unearthing them and eventually assisting them 

 to hatch, all as if she were merely a machine wound up and set in 

 motion by definite external and internal stimuli. But closer study of 

 her reflexes, especially under changed conditions, shows that matters 

 are not so simple as they seem. Gaps may be formed in the series 

 of activities without affecting the outcome. Thus the excavation of 

 the nest may be omitted if the insect finds some preexisting cavity 

 under a stone, in a gall or in an artificial nest, or when she is adopted by 

 a number of workers of her own or another species, without in the least 

 disturbing her subsequent reactions. Or, if food is placed in the nest, 

 the young may be fed with it instead of with the maternal secretions, 

 or some of the eggs or larvae may be devoured by the mother for the 

 sake of nourishing the remainder of the brood, etc. Moreover, the 

 young may not all mature at the same time and must, therefore, be 

 treated differently, according to their respective ontogenetic stages. In 

 short, the activities, though all tending towards one end, the matura- 

 tion of the brood, are, nevertheless, organically and very flexibly 

 combined. This is even more apparent when we come to compare the 



