36 Riley Presidential Address. 



hill-making species of the genus Termes, which attain greatest 

 perfection in South Africa. These nests always arise from the 

 ground, and vary according to the species. They are made of 

 finely comminuted wood, mixed with some secretion, or of clay, 

 in which case they become as hard as stone. Long subterranean 

 foraging galleries are extended from these nests. 



In South America some species seem merely to excavate sub 

 terranean galleries in the soil, while Bates found at Santarem, 

 Brazil, composite nests occupied by different species, which built 

 each its own part of the nest with its own special material. 



SOME GENERALIZATIONS. 



In the hasty summary which I have thus endeavored to present 

 to you of some of the chief characteristics of social insects, those 

 who are most familiar with the facts can best appreciate how 

 much of interest has been omitted. These insects are attacked 

 by various natural enemies in their own class, and particularly 

 in the case of the bees and wasps, by some of the most abnormal 

 parasites, viz., the Stylopida?, in which the young larva is ex 

 tremely active, but the adult female stationary and so degraded 

 that she has lost all members and mouth-parts,, and in fact all 

 semblance of an insect, while the adult male is an active, winged 

 creature, of very ephemeral existence. Chapters might be writ 

 ten upon the myrmecophilous and termitophilous insects of var 

 ious orders, some of which are mere mess-mates, others advanta 

 geous associates, while others are unwelcome, but more or less 

 successful intruders on the hospitality of their hosts. This part 

 of the subject must, however, be passed over in order to permit 

 me to close with some generalizations and speculations which the 

 facts already enumerated provoke. 



THE SENSES IN INSECTS. 



Having thus dealt, in a summary way, with some of the struct 

 ures and economies of the social insects, let us now consider their 

 psychological manifestations. 



Of the five ordinary senses recognized in ourselves and most 

 higher animals, insects have, beyond all doubt, the sense of sight, 

 and there can be as little question that they possess the senses of 

 touch, taste, smell and hearing. Yet, save, perhaps, that of 

 touch, none of these senses, as possessed by insects, can be strictly 

 compared with our own, while there is the best of evidence that 



