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THE YOUNG NATURALIST. 



necessarily, and as a rule do not. The merest tyro in Coleoptera must ex- 

 amine the legs, antennas, &c. of his captures in detail, as well as the markings 

 on the elytra. It is a decided step in advance to discuss such quesiions as 

 the " Origin of Apterous Females," and I am not entering into the discussion 

 with any positive knowledge on the subject, bat it is not a new one with me, 

 and I made a suggestion on the subject in the Y.N. for December, 1883 

 (see Y.N. Yol. v. p. 16.) My main reason for entering into the discussion 

 so early is to call attention to what appears to me to be an error in both the 

 papers that have appeared, viz. that the primary cause has been the crippled 

 wings of some progenitors of these species. I think we may take it for 

 granted that the axiom "like produces like" does not necessarily apply in 

 such a case as the non-expansion of the wing of a butterfly or moth. Mr. 

 Darwin produces many illustrations to show that the disuse of an organ will 

 diminish it both in size and power, but he says " The evidence that accidental 

 mutilations can be inherited is at present not decisive" [Origin of Species, 

 6th Ed., p. 108), nor am I aware of any subsequent illustrations confirming 

 the idea. Disuse, however, will unquestionably cause a diminution in size 

 and power of any organ, and the females of the four genera Mr. Anderson 

 refers to (PhigaUa, Nyssa, Hyhernia, and Cheimatobia) , are not by any means 

 the only insects that are without wings. Many beetles are in the same state 

 and some actually have rudimentary membranes, below elytra that are 

 joined at the suture, and could not possibly be raised for flight. 



I would take it for granted then that the reason why these species have 

 rudimentary wings only, is because it was to their advantage not to use them, 

 and that those who used them least were least likely to transmit large and 

 strong wings to their descendants. The remarkable case, so often quoted, of 

 the beetles of Madeira, may be repeated here, though it is probably well 

 known to most of the readers of the magazine. Mr. Wollaston discovered 

 the remarkable fact that in Madeira, an island much visited by strong winds, 

 there is the enormous proportion of 220 out of 550 species of beetles inhabit- 

 ing the island that cannot fly, and of u twenty-nine endemic genera, no less 

 than twenty-three have all their species in that condition." Here, at Hartle- 

 pool, and no doubt everywhere else on the coast, the sands and sand banks 

 are about the best possible ground for collecting coleoptera. With a west 

 wind, that is from the land to the sea, thousands of beetles are blown on to 

 the beach and into the sea. Many, of course, are drowned, but those that 

 fall on the sand endeavour to make their way back again to the banks, and 

 may be picked by the collector. In Madeira, a comparatively small island, 

 subject to strong winds, the proportion of wingless beetles is too great for it 

 to have been accidental. Mr. Wollaston also pointed out " that certain large 



