(690 REPORT — 1894. 



which .belong to a different cider (Platyptera),* much older in time according to 

 the palseontological record — an order in which the young are born in the image of 

 the parent and are more or less independent from birth — one would expect to find 

 larval nurture and environment less potent in influencing ultimate structure. Yet 

 all the facts known, and particularly the late most painstaking observations and 

 experiments of Grassi, prove conclusively that here, also, the young are dependent 

 upon the nurses, and, more remarkable still, may be diverted, according to the food 

 and treatment given, to any of the four castes which characterise the typical 

 termite colony, there being, in addition to the male and female, two kinds of 

 neuters, viz., soldiers and workers, as in the true ants. In the first larval stage, or 

 when first hatched, the individuals are, to all appearances, absolutely alike, and each 

 possesses the potentiality of becoming either a worker, or a soldier, or a perfect sexed 

 individual. Nay, further, the pupse, or nymphs, may be diverted into reproductive 

 forms which never acquire wings and which are called supplementary queens and 

 kings; and even larvae may be so diverted into reproductive forms, with no further 

 external structural development, when they become complementary or neotinic 

 kings and queens. 



The steps in the development from the simpler to the more special structures 

 and attributes belonging to the species with the most perfect social organisation 

 may be traced in the diiferent species and genera of their respective families in all 

 social insects of the present day. The amount of variation is often great in the 

 ants and termites, where the environment is less fixed than in the bees and wasps, 

 and this variation, among termites, is particularly manifest in the economy of the 

 same species, as exemplified in Euterines, which the author has studied in the West 

 Indies, and in which the number of queens varies from one to nine or more. It is 

 not generally known, but it is a fact, that existing termites (using the term in the 

 broader sense, so as to include several genera) exemplify all the steps in develop- 

 ment from species which are active in broad daylight (the neuters having faceted 

 eyes and dark integument, and, so far as is known, no definite nest or termitary), 

 to the more specialised species in which the economy and division of labour are 

 most perfect, and in which the neuters and soldiers are blind and always work in 

 the dark and build elaborate structures. Further, the neuters in termites are truly 

 without sex or are modified individuals which might have produced either sex ; 

 while in the Hymenoptera they are invariably modified females. 



In so fiir as these ditt'erent forms of neuter insects depend for their development 

 on the food and treatment given by the nurses, they are outside the domain of 

 natural selection. The author believes, however, that there is a potential, inherited 

 tendency in the young larva to develop in the various directions that have been 

 fixed for each species in its past development, as he cannot believe, e.//., that young 

 larvsB taken from one species of termites, and brought up under the care of the 

 nurses of any other species, can be diverted to the forms peculiar to this last. There 

 is a possibility, since the food of these young in the social insects consists largely of 

 secretions from the nurses, that these secretions may so influence the changes as to 

 confine them to the specific forms of its own specios, regardless of the parentage of 

 the young. That there can be any such powerful influence of nurture as would 

 neutralise and overcome the inherited tendencies of species is, however, extremely 

 improbable : its bare possibility opens up a most interesting field for experiment, 

 which is easily made, and doubtless soon will be made. 



The author believes, with Darwin, that ths variations in social insects have 

 been guided by natural selection among colonies, but that there has also been what 

 he calls social selection araoug individuals. Competition has been between colonies 

 rather than individuals, and those colonies which liave acquired, through heredity, 

 the habit of producing, from one or more fertile females, the diflerent castes 

 characteristic of the species have, in course of time, survived. He believes, how- 

 ever, that this colony-selection, as well as the social selection among individuals, 

 has been not only along lines that were and are useful to the species, but along lines 

 of secondary utility, and even along lines which are purely fortuitous and still most 

 variable and unfixed. 



Finally, as between Weismann's views and those held by Darwin himself, the 



