Social Insects. 3 



surprising that its members have been very generally imbued 

 with the spirit and interpretations which the illustrious author 

 of " The Origin of Species " gave to the phenomena of life upon 

 our planet. Not that they have been blind followers of the 

 school which believes in the all-sufficiency of natural selection 

 to account for life-phenomena ; for a review of the communica 

 tions and discussions and particularly of the addresses which 

 have been delivered by my predecessors will show that in the 

 search after truth, the ideas of Lamarck and others, who have 

 pregnantly speculated on the philosophy of life, have been duly 

 appreciated. Upon the one great question which, more than any 

 other, has occupied biologists of late years, viz., whether function 

 ally acquired characters are transmitted by heredity, there have 

 been few more able contributions to the subject anywhere 

 published than the papers and addresses of my distinguished 

 predecessor, Prof. Lester F. Ward. Indeed, aside from the 

 reasons already given, the choice of my subject to-night was in 

 no small degree determined by an admission in one of his more 

 recent and yet unpublished communications to the society, to the 

 effect that the characters of neuters among the social insects 

 offer the greatest stumbling block to the theory of the heredity 

 of such acquired characters. 



ORGANIZED INSECT SOCIETIES. 



The social insects, or those which live in communities, and 

 particularly those of the order Hymenoptera, which possess highly 

 developed social characteristics, have, from the very earliest 

 times, intensely interested the student of insect life. There are 

 insects of other orders which are either social normally or be 

 come so by exception and for special purposes. Thus many 

 Lepidopterous larvse live together when young, but scatter when 

 they grow older. In some cases there would seem to be no par 

 ticular purpose in the association ; in others, as in the common 

 Tent Caterpillars (Clisiocampa spp.) the well-known Fall Web- 

 worm of North America (Hyphantria cunea) and many similar 

 species of other countries, the association is of a somewhat 

 higher character, as the larvae build a common web into which 

 they retire at stated periods, and which helps to protect them 

 both from the inclemencies of the weather and from the attacks of 

 birds and other enemies. The highest development of this 



