:550 THE ENTOMOLOGIST. 



years ago by my friend the late Rev. G. A. Smallwood, in company 

 with whom I found it on a railway embankment between Burton -on- 

 Trent and Derby ; and this year I have again found it in Shropshire. 

 The larva feeds on the leaves of the common yarrow [Achillea mille- 

 folium), and is full-grown during the month of October. It is light 

 brown in colour, somewhat variable, but generally having "chevrons" 

 of a darker brown along the back. Mr. Smallwood led me to think 

 that it preferred to rest upon the flowering stems, but this I find on a 

 closer acquaintance is by no means always the case, as I found it here 

 stretched at full length along the midrib of a leaf, and in some cases 

 on withered leaves, in which position of course it is anything but 

 conspicuous. And sometimes, too, it curls itself into that graceful 

 shape known, I believe, as that of the "ionic volute,'" this being 

 especially the case when it rests on the flowering-stems. Sunny banks 

 under hedgerows, particularly where the soil is sandy, appear to be 

 the favourite locality, and it was in such situations that I found most 

 of mine this month, though I went rather too late, i-iz. on the 23rd ; 

 and there was plenty of evidence that I should have done much better 

 a week or ten days earlier. However, this will be a hint for another 

 season, and I hope to profit by it. Perhaps some of your readers, 

 especially among the younger " hands," may do the like. I should 

 like to add that this larva presents a striking example of "protective 

 coloration," its appearance both when curled up and stretched out at 

 full length being remarkably like that of the brown and withered 

 leaves so frequently seen upon the plants of yarrow. — (Eev.) Chas. F. 

 Thornewill ; Calverhall Vicarage, Whitchurch, Salop, Oct. 24th, 1901. 



Evolution' in Butterfly Scales. — At a meeting of the Manchester 

 Microscopical Society, held on November 7th, at the Grand Hotel, 

 Manchester, Mr. Mark L. Sykes. F.R.M.S., read a paper on " Evolution 

 in Butterfly Scales." With reference to butterflies, he said that in 

 whatever direction the mimicry may tend, whether in simulation of 

 inanimate objects, such as leaves or twigs or moss, for concealment 

 from their enemies on the one hand, or to enable them to more easily 

 secure their prey on the other — in mimicry of conspicuously marked 

 or highly-coloured inedible by edible species, in resemblance between 

 two or more equally distasteful but entirely different species, or what- 

 ever purpose the mimicry may serve — it seems that the resemblance is 

 in outward appearance only. Although the similarity in colour pattern 

 and markings may be so close as to be almost identical, microscopical 

 examination of the wing scales of these insects shows that the details 

 by which the likenesses are brought about may be, and often are, 

 widely different. The specimens from which the examples have been 

 taken fall under two groups of mimicry — that of MilUer and that of 

 Bates. The Miillerian form of mimicry is that in which two or more 

 highly coloured, conspicuously marked, or peculiarly shaped butterflies, 

 all inedible and distasteful to the insect-eating animals, are so closely 

 alike as to be easily mistaken one for the other. These by their 

 similarity in appearance aftbrd each other mutual protection, by 

 dividing between them the total number destroyed by the young 

 insectivora of each season in learning what is and what is not good 

 for food. The Batesian mimicry is that in which certain of the con- 



