270 



BARDWJCKE'S SCIENCE-GOSSIP. 



hibernated insects seen earlier. It is curious that 

 1876 (the only great Edusa year which I have known), 

 was not distinguished by any " burst " of the species 

 in England, but that the following year (1877) was 

 a great Edusa year in England, while here it 

 produced only a few specimens. The progeny of 

 the 1S76 swarm, however, continued to show itself 

 in steadily diminishing numbers, during three con- 

 secutive summers, since the last of which I have 

 seen altogether two specimens, one in July, 1S87, 

 and one on Sept. 30th, 1892. I may also remark 

 that my experience in 1876 quite coincided with Mr. 

 Creaghe-Haward's in 1892, as to the immensely 

 superior numbers of the male sex. I think ten to 

 one would not be too high — at any rate not much 

 too high — an estimate. This scarcity of the females, 

 if general, will serve to explain in some measure, 

 how such remarkable outbursts of Edusa, as those 

 under notice, have been immediately followed by 

 years in which the same insect was by no means 

 unusually abundant. 



C. B. Moffat. 

 Ballyhyland, Co. Wexford. 



MOTHS AND SALLOWS. 



MR. J. R. HOLT'S more recent notes remind 

 me that his communication under the above 

 heading, which appeared in Science-Gossip for 

 January, has elicited no response. Mr. Holt thinks 

 the relation of the moth to the sallow unsatisfactory, 

 in the present state of our knowledge, and the two 

 difficulties which he brings forward have proved 

 their formidableness, by the length of time they have 

 held the field. But considering the situations chiefly 

 affected by willows, I cannot think them good 

 subjects for unaided wind-fertilization. Moths well- 

 dusted with the pollen might, I submit, materially 

 aid the wind in its fertilizing mission ; since, on their 

 mounting into the air, the pollen shaken from their 

 plumage, would manifestly have a very much im- 

 proved chance of being wafted to a distance. Here, 

 however, I am confronted by the tough part of Mr. 

 Holt's conundrum ; for at first sight it seems absurd 

 to maintain, that the sweet secretion attracts moths, 

 that they may carry the pollen upwards in their 

 flight ; and yet, in apparent defiance of its own 

 purpose actually stupefies the moths, and keeps 

 them stationary. To extricate ourselves from this 

 entanglement, it is necessary to consider how a moth 

 would probably act, were it attracted to the willows 

 and not stupified. I apprehend that, having once 

 arrived at .1 tree laden with flower, the moth would 

 merely flit from catkin to catkin, disturbing pollen 

 enough to fertilize a forest, yet doing little or no 

 good— none, that is, beyond what the lightest breath 

 of air would have an equal chance of effecting. 

 Indeed, as the pollen of a willow is totally wasted 



unless it reaches one of the opposite sex, and as the 

 Nocture generally delight in still weather, and would 

 consequently cause the greatest displacement of 

 pollen on the very nights when it was least likely to 

 be borne to any appreciable distance, it appears to 

 follow that a host of moths would, under such 

 conditions, be rather objectionable than desirable 

 visitors. From this point of view I conceive the 

 narcotic property in question, to have been acquired 

 as a security against waste. The moths continue 

 under its influence only for a few hours, and, having 

 passed the night on the sallow-catkins, towards 

 morning recover from their drowsiness and wheel 

 away, each scattering his little cloud of dust to the 

 light breeze. And bearing in mind how a willow 

 in full season is sometimes crowded with these 

 " filmy shapes that haunt the dusk," I think we have 

 little reason to doubt that their dispersion, at the 

 close of a revel, constitutes a not unimportant stage in 

 the somewhat complicated story of willow-fertilization. 



C. B. M. 



SEXUAL SELECTION. 



THIS I take to be but an emphasised phase of a 

 propensity, the existence of which, in some 

 degree, is abolutely indispensable to the origination of 

 any new species. For it is admitted on every side, 

 that the tendency to originate a new species must be 

 defeated, if the individuals which have begun to 

 develop specific differentiation, long continue to mate 

 with those of the older form, from which they are an 

 offshoot. Now, though a species may be spoken of 

 as descended from an ancestral pair, it cannot be 

 assumed that the deviation from the type which 

 characterises the offspring, simultaneously occurred 

 in both the parents. On the contrary, it should be 

 supposed to have occurred only in one. Let us 

 suppose a case in which the deviation occurred in 

 the male, and it follows that the first female an- 

 cestor contributed nothing to the evolution of the 

 species, beyond transmitting to her daughters the 

 predisposition to admire males fashioned after the 

 pattern of her own spouse. Have we not here the 

 force of sexual selection brought immediately into 

 full play ? And supposing the deviation to occur in 

 the female, would not the permanence of the species 

 require the development of the same force ? This, it 

 appears to me, might be effected in one of two ways. 

 The simpler but far less usual course would be for 

 the female to reverse the rules of courtship, and take 

 the initiative herself, as in the example of the grey 

 phalarope ; in that case, of course, the distinctive 

 marks of the species would be more strongly 

 developed in the female than in the male. Ac- 

 cording to the more probable order of events, the 

 variation in the female would, I think, remain a mere 

 precarious variety in that sex, until the peculiarity 



