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deeply into the morphology of the subject, and perhaps 

 almost entirely ignores its physiological aspect. 



Recognising that solutions of some of the more complex 

 problems of biology might be arrived at through entomology, 

 some of the leading scientific men of the day turned their 

 attention to the investigation of insect life, and this depart- 

 ment of the study, which is largely philosophical, has 

 attracted many students. Of course, theory, more or less 

 speculative, largely obtains ; but exception cannot be taken 

 to this, as many, perhaps it might be said most, of the now 

 generally accepted facts in science, were each, once on a 

 time, known as Mr. So and So's theory. 



Some students of philosophical entomology have, un- 

 fortunately, not hesitated to express a want of sympathy, 

 not only with the field-worker or collector, but also with 

 the describer of species. Curiously, however, they seem to 

 have overlooked the fact that both the classes of entomo- 

 logists they affect to contemn have conjointly been the 

 means of bringing together and preparing in intelligible 

 form the very material that is most useful to them for their 

 work. 



Without entering very far into the philosophical phase of 

 his subject, every practical entomologist has it in his power 

 to contribute something towards solving one or the other of 

 the problems connected with variation, heredity, and the 

 general laws operating in the production of species. He is 

 already expert at rearing insects from the egg ; let him 

 continue to do this, but let him conduct his rearing opera- 

 tions on experimental lines. It would be a comparatively 

 easy matter to make observations relative to the proportions 

 of a brood favouring the known parents of that brood. As 

 a rule, perhaps the female only is positively known ; but 

 even in such cases statistics of variation in the progeny 

 would be interesting, and especially so if the female was of a 

 more or less striking form. 



A useful course of experimental work would be to endeavour 

 to develop some particular varietal tendency exhibited by a 

 species. We all know that in most, if not all, polymorphic 

 species of Lepidoptera there are light and dark forms. Now 

 it is quite possible that by judicious selection of a stock and 

 careful manipulation of the subsequent broods, an entirely 

 light or dark race might be established of any species in 

 which the initial stage of the required variation was shown. 

 In starting an experiment of this nature the first thing to do 

 would be to secure ova from three or four females varying 



