6154 



Entomological Society. 



difference of species, a greater difference of food would of course produce a greater 

 apparent difference of species, and thus each genus might be assumed to consist of 

 only a single species, varying according to its food and other ciicumslances. 



" Hence species are not ; they tvere merely phantoms of the brain of the naturalist. 



"The difference between the two specimens of Cemiostoma I have exhibited is 

 not a specific difference; Scitella, driven by stress of weather far from its usual food, 

 laid eggs on Lotus, and thus produced an apparently new species. It is of course an 

 interesting problem whether, if this insect bred from the Lotus were to deposit eggs 

 on an apple-leaf the result would not be some other aberrant creature, which the 

 first captor would hold to be a new species till an elaborate investigation into its pedi- 

 gree should show that it was descended from Scitella, out of Lotus, by Scitella, 

 out of apple. 



" Such theories would never have been started but for the smallness of the 

 objects under discussion. 



" I have also brought for exhibition two hitherto reputed distinct species of 

 butterflies, of the genus Vanessa ; but as they are very similar in appearance, and feed 

 on plants of the same natural order, Urticacece, perhaps the Meeting will now be dis- 

 posed to consider Polychloros and Urticae as one species : it will of course be 

 remarked that the flight of these two insects is very different, that of Polychloros 

 being far the more powerful ; but then it must be borne in mind that elm trees grow 

 higher than nettles, and consequently a butterfly bred from an elm tree might be 

 expected to be endowed, on that very account, with stronger organs of flight. 



" I could multiply similar instances ad nauseam; but really I feel that 1 am un- 

 necessarily taking up the time of this Meeting, and I should not have recurred 

 to the subject but for the number of young entomologists who now attend our 

 Meetings, on some of whom the idea of gradual developments from one species to 

 another might have most injurious effects, were it not briefly, yet effectually, 

 exploded." 



Mr. Westwood considered it would require far greater research than had yet been 

 made, and far more argument than the few lines Mr. Slainton had just read, to dis- 

 prove the theory he had advanced at the last Meeting, although Mr. Stainton was 

 pleased to imiigine he had " effectually exploded " the idea of gradual developments, 

 yet he (Mr. Westwood) still maintained that many of the supposed new species of 

 Micro-Lepidoptera lately established might be merely modifications of other species 

 dependent on diversity of food or other circumstances with which we are not 

 acquainted. That many species of animals, including insects, underwent modifica- 

 tions and became, so to speak, geographical or structural sub-species was well 

 established, as might be seen in Mr. Wollaston's work on " Species," since the publi- 

 cation of which a great change had taken place in the minds, especially of German 

 naturalists, as to the specific rank of many of the supposed species of Carabideous in- 

 sects, which were now sunk into local sub-species. It was not suflBcient to say that 

 larvae which had fed on the oak, would die rather than feed on any other tree, because 

 the experiment was tried with an individual which had already become quercivorous. 

 Many of the best botanists had also adopted the theory of local sub-species ; it was 

 quite necessary to register these permanent or even transitory sub-species, but far 

 more philosophical to endeavour to discover the centre, so to speak, from which they 

 radiated. 



