2l8 



HARDWICKE'S SCIENCE-GOSSIP, 



humanity," and "as emissaries of the devil, and the 

 ghosts of heretics." Flies have always been dis- 

 tinguished for evil ; they were one of the plagues of 

 Egypt, now afflicted with irritations of another Order. 

 The fly has curious habits ; it is persistent in attack, 

 and repels interference. Most insects seek safety when 

 meddled with, but the more a fly is buffeted, the 

 more eager he is to return, and generally to the same 

 spot. The perseverance of their attack is extraordinar}-. 

 An individual " forest fly " will follow a horse for 

 miles, and they have been known to travel to London 

 in cattle vans containing New Forest ponies, and 

 causing the direst excitement at Waterloo Station 

 among the town acclimatised cab-horses. 



It is somewhat surprising, considering the numbers 

 deposited by each individual insect, how rarely, 

 unless specially sought for, the eggs are discovered. 

 Doubtless insectivorous birds clear off those most 

 prominently placed, and it is possible that many rare 

 eggs of the lepidoptera might be found in their crops 

 and intestines — an idea supported by a very unicjue 

 observation lately made by Mr. Tegetmeier, and 

 graphically described by him in the "Field" of the 

 30th of August last. The rare incident of a cuckoo 

 captured in the gardens of the old Charterhouse, 

 in the very centre of Loudon, afforded the oppor- 

 tunity of examining the contents of its gizzard. It 

 was found full of a. "mass of dark fragments com- 

 posed of the wings and bodies of insects, skins of 

 caterpillars mingled with an infinite number of small 

 white granules." The writer had the opportunity of 

 first seeing these white granules under the microscope. 

 They proved to be the eggs of a moth — afterwards 

 identified as those of the Vapourer {Orgyia antiqua). 

 When washed and carefully dried, they were as intact 

 as when laid, and, notwithstanding the ordeal they 

 had undergone, with care, and under favourable cir- 

 cumstances, might be hatched. Mr. Tegetmeier is 

 under the impression the bird fed freely on fertile 

 insects, the eggs retaining a vitality which prevented 

 their digestion, but it is possible the passive moth, 

 lingering over her deposit, was swallowed with her 

 treasure in one " bonne bouche." However this may 

 be, it is a curious and interesting observation, and 

 may lead to the examination of gizzards and in- 

 testines of birds for the discovery of objects of this 

 character, otherwise unattainable. 



Specimens are easily prepared and mounted for 

 the cabinet, the only difficulty is to destroy vitality, 

 without spoiling their beauty ; immersion in alcohol 

 touching each with a hot needle, has been suggested, 

 but a dip in water just under boiling-point is effectual, 

 and in some cases improves their appearance. Before 

 mounted, they must be carefully dried. Opalescent or 

 iridescent eggs are seen to the Isest advantage empty, 

 as mere shells, after the larvse have escajsed ; this 

 especially applies to the eggs of parasites attached to 

 hairs, or featliers. 

 Crouch End. 



THE ORIGIN OF DOUBLE FLOWERS. 



N/T R. IMOTT'S article, following the suggestive 

 J- one by Mr. Gibbs, has elicited my admiration 

 as an effort of a priori reasoning. His preliminary 

 observations command the assent of the understanding, 

 and his law of the wave-form or force-wave is 

 simply Herbert Spencer's law of rhythm as laid down 

 in the First Principles. But I fail to see by what 

 process, inductive or deductive, he arrives at the 

 conclusion that " the double flower should indicate 

 the climax of a species." In the previous sentence 

 he says, "But as the climacteric of the species 

 approached the individuals attaining more complete 

 development, those organics at the terminal growing- 

 points which formed the reproductive element, 

 would now unfold into perfect petals, and reproduction 

 would gradually cease." This sentence implies, to my 

 mind, that Mr. Mottregardsachangefromreproductive 

 organs to perfect petals as indicative of more com- 

 plete development. Much depends upon the mean- 

 ing of the word "development." I take it that an 

 advance in development means more complete differ- 

 entiation so as to secure a more thorough subdivision 

 of labour, and I believe that is the vievi' entertained 

 by most biologists. If that is so, the presence of 

 leaves, petals, and stamens (for example) in the same 

 plant would represent a greater differentiation than 

 the presence of petals and leaves only, and conse- 

 quently a higher stage of development. If petals 

 and stamens are specialised leaves, one would regard 

 the petals as being less altered from the leaf-form 

 than the stamens, and therefore an approach of the 

 latter to the petaloid state would signify an approach 

 to homogeneity in the organs of the plant — in other 

 words an approach to the reverse of differentiation 

 and of the complete development referred to by 

 Mr. Mott, The stamens must be regaixled as being 

 of more direct importance to the plant than the 

 petal which is merely a protection to the reproductive 

 organs, or a means to fertilisation. In the absence of 

 the stamens the petal is without function. What 

 then can be the benefit to a plant when its stamens 

 are metamorphosed into petals ? Can a plant be said 

 to be more highly developed because it has produced 

 organs which are of no use to it? Such a change, as 

 of stamens into petals, I should say, is a decided 

 retrograde movement, and occurs rather when the 

 species has passed its climax than at the time it 

 actually attains that point. One may perceive how 

 that owing to the easy circumstances of a species that 

 has been successful in the competition for existence, 

 the energy requisite for producing reproductive organs 

 may be lacking, though sufficient to produce these 

 petaloid representatives. But by the time this stage 

 is reached the species must already be on its down- 

 ward career. 



In arriving- at the probable cause of variability, 

 Mr. Mott says, "Plants which are perpetually self- 



