202 THE entomologist's record. 



of quite a mass of eyes, all bound together, each of which has a separate 

 hexagonal facet, the surface of the compound eye being strongly convex. 

 Yet with such an apparently well-developed eye, the organ as an optical 

 instrument is very defective ; practical experiment has proved that with 

 the exception of a remarkable power to discriminate masses of colour, 

 of a keen appreciation of slight differences of light and shade, and of 

 an ability to recognise objects in motion, the eyes of most insects are 

 practically useless, and so far as the sight of the white butterfly is con- 

 cerned, we have seen that it is attracted by anything of its own colour 

 as quickly as l)y a female of its own kind." What an overturning of 

 many of our old ideas ! 



Mr. Tutt's great subject, " Variation," too, is once more in evidence. 

 The vagaries of the Carpet moths are glanced at. These are discovered 

 both in the wood and on the mountain side, now as patches and 

 scars on the tree-trunks, now as lepidopterous cracks and crannies of 

 the rocks. The blackening of the resting-places of moths by the vast 

 and continuous eruptions of smoke in manufacturing centres is ex- 

 plained, and the great axiom is driven home that nothing in nature is 

 fixed, everything is variable and capable of adaptation to its surround- 

 ings, this adaptation ensuring the continued existence of the species. 

 Besides, of course, the form and origin of markings which are pro- 

 tective are speculated upon, and, speaking of the metallic spots and 

 blotches displayed on the underside of the larger Fritillaries (Argi/miis 

 aglakt being the species particularly referred to), Mr. Tutt writes : — 



" We may obtain a clue to the manner in whicli these silver spots 

 have been developed from the relatives of this butterfly. Very many 

 of these have sjiots somewhat similar in shape and position to those we 

 see liere, but in some species they are pale yellow, in others white, 

 whilst in many the spots are more or less of this metallic character. Is 

 there any connection between the three colours ? Yes, it would appear 

 from what we know that one is derived from the other ; probably the 

 yellow gives rise to white, and this in turn to the metallic silveiy white. 

 In a vei'y near relation, the High Brown Fritillary (Argi/nnis adippe), 

 we find specimens which shows every possible gradation of size and 

 development, as regards the spots, from entire absence of silver when 

 the spots are pale yellow or whitish, until the spots unite to form silvery 

 streaks. Here, then, the transition is very evident, and when we turn 

 to those species in which the silver markings are now so fixed and con- 

 stant, there can be but little doubt in our minds that the development 

 has been a result of natural selection, and is of the greatest possible 

 service to the insect. The insect before us closes its wings. How in- 

 conspicuous it at once becomes, for, as it clings closely to a thistle-head, 

 the shiny spots resemble very distinctly the shiny bracts around the 

 capitulum on which the sun is shining." 



But the other orders of insects are not neglected, nor is the economic 

 side of our science forgotten. We have discpiisitions on galls, and on 

 the damage caused by Sesia, Zeuzera, Agrotis, Torlrix and many others 

 whose habits of living are so destructive to trees, roots and grain. The 

 varying metamorphoses of the dragon flies ond grasshoi:)pers, and the 

 economies of the social Hymenoptera, are described and commented on, 

 and while dealing with the last, Mr. Tutt gives the following explana- 

 tion of the origin of the system of slavery prevalent in the nests of 

 certain ants : — 



