EXPERIMENTAL ENTOMOLOGY. 27 



current propositions that do not even purport to be founded on 

 observation, and there is little use in attempting to test these. It is 

 with observation that experimentation is especially concerned, and the 

 development of the one is therefore in practice closely related to that 

 of the other. The growth in recent times of observation is illustrated 

 by the increasing number of serial and other publications chiefly 

 devoted to it, to descriptions of form and structure, external and 

 internal, set forth in terms of scientific precision. It is, however, to 

 another class of observations, that connected with functions, instincts 

 and habits, that I would direct special attention, urging that we should 

 have an increase in the supply of these from contributors who will make 

 their observations systematic and complete. 



No entomologist can fail to appreciate a good collection, but the 

 strangely multiform objects, often surprisingly beautiful in colour and 

 attractive in form, that we admire and study in our cabinets, are 

 nothing more than decorative corpses. They represent so much only as 

 can be preserved of the outcome of the life which constructed them, 

 which is their ramm ifctrc, and gives them their supreme claim to be 

 investigated. We may speak of life as a succession of functions, and 

 the investigation of these functions is consequently of the very highest 

 interest. It is not an easy task. The something that is called life 

 we have indeed in common with the insects ; some of their senses, 

 some of their external and internal organs in many fundamental par- 

 ticulars resemble our own, but the points of difference are innumerable 

 and profound, affording abundant scope for imagination and conjecture, of 

 the opportunity for which advantage has been abundantly taken. Happily 

 the scientific spirit is gaining in all that pretends to be knowledge, 

 and, whenever a theory that is merely plausible can be verified by 

 actual experiment, insists that it shall be so verified. Accordingly we 

 find that experimentation is making way in entomology, as it is doing 

 in other departments of knowledge, and the latter part of the century 

 has witnessed a remarkable increase in the application to entomology 

 of this touchstone of truth, Avhich is at the same time a source of hght. 



An enumeration of the kinds of functions and habits our know- 

 ledge of Avhich has been greatly extended by the researches of recent 

 years, would be a lengthy one. Among them may be mentioned the 

 functions of the antenna, those elaborate organs that seem to belong 

 to another world of sense, the methods by which insects travel over 

 smooth surfaces, the process by which the legless pupa climbs out of 

 its larval skin to find a point of attachment above, the manner in 

 which wings are formed and expanded and the scales upon them are 

 evolved, the mechanism of flight, the nature of stings and the opera- 

 tion of the poisons they contain, the source and nature of the pigmental 

 and other colours, the nature and scope of the visual perception of 

 insects, their sense of taste, the faculty we call " scent," which enables 

 them to discover objects at great distances, where neither light nor 

 sound can assist in the discovery, the wonderful variety of apparatus 

 for generating and difiusing scent, urtication by larvje and whether it 

 is assisted by a specific poison as asserted by M. Fabre, the luminosity 

 of many species, and the strange situation and structure of oi'gans of 

 hearing, and of the machinery for stridulation with which many are pro- 

 vided. 



Mr. Packard's Tcjt JJooh- of Kutoiuihujij contains references to most 



