296 THE entomologist's recokd. 



study is practically lost to the cause of science. It is an illustration of 

 that peculiar custom which so many entomologists have of preferring 

 the study of dried-up specimens to that of the actual living forms. If 

 an insect is an interesting object when in the cabinet, how much more 

 interesting must it be while in the living state, and then too, 

 the long and tedious process over which so much time is often wasted 

 — setting — is avoided I Although a few of the usual wholesale larval 

 breeding experiments may have occasionally had good results, yet 

 unless some thorough system is adopted, success rests only upon chance, 

 and much valuable time and Avork are likely to be wasted. 



In Nature there is a cause for every effect, and there is not a single 

 detail of colour, form or action but has some special function to 

 fulfil. One of the great laws of Nature is, " That under the same con- 

 ditions the same cause will ahvays produce the same effect," therefore it 

 is clearly evident that all variations of form must have some source, as 

 unless there were some reason for this variation, all forms would always 

 be, in every respect, exactly the same as their parents. Before much 

 can really be learnt about a variet}^ it is first necessary to find out as 

 much as possible about the particular cause which compelled it to alter 

 from the usual type. To begin with, one must ask oneself such ques- 

 tions as, " What is the reason for this marking? " ••' What is the cause 

 of this shape?" "Why does this species fly in the sunlight?" etc., 

 and however complex and difficult the question may be there is 

 the consolation of knowing that somewhere or other there is a satis- 

 factory answer to it ; and the harder this is to discover the greater will 

 be the reward when the problem is solved. One of the greatest diffi- 

 culties to overcome is, I think, the "loss of varying power," into 

 which state so many species api)ear to have more or less fallen by 

 the process of " natural selection." 



As the " struggle for existence " in past generations between the 

 preying and the preyed-u^^on forms grew stronger, the force of offence 

 on the part of the one, and defence on that of the other, brought each 

 nearer and nearer to perfection ; so that, after a certain time, by this 

 constant improvement, each form would become as nearly perfect as 

 was possible for it. It is clear that Avhen arrived at this state, the 

 only possil)le variation must be in the wrong direction. This would 

 mean annihilation for such forms, as they, not being in the same 

 way so well protected as the main stock, would, in all probability be 

 the first to be picked off by one of the enemies of the race, and thus 

 gradually by " natural selection " all such weak varieties would die out, 

 leaving only the approximately perfect forms to become the parents of 

 all future generations. The descendants of these, being governed by 

 exactly the same laws as were their ancestors, and being kept up by 

 their enemies to the same standpoint of perfection, would gradually, by 

 their law of inheritance, lose to a great extent their old power of 

 varying. Tims it is now a very difficult matter to produce in a short 

 time with certainty, anj'^ great variations from old and long-fixed forms, 

 but by removing as much as possible all enemies and other hindering 

 forces for a considerable number of consecutive generations and sub- 

 stituting in their place new forces such as artificial selection, with a 

 certain amount of perseverance good results ought to be obtained. — 

 Alfred J. Johnson, Boldmere, Erdington. October 21st, 1893. 



