some tiest-attihides of Buttcrjiies. 113 



Intimately bouuJ up with the attitude at rest is the 

 question wiiether or no insects select resting-places of a 

 character likely to make tlie most, so to say, of their 

 cryptic colouring. 



Many years ago the late Mr. Geo. Norman and myself 

 took a lot of Polia rhi, L., at rest close to the liydropathic 

 establishment at Forres, and we were much puzzled by the 

 fact that while many were taken on whitewashed walls, 

 where they were difficult to detect, quite as many were 

 found resting on dark tree-trunks and could be easily seen 

 at many yards' distance, 



Mi\ Hamm has made some striking observations tending 

 to an affirmative answer to this question.* In the Baghi 

 Forest, near Simla, I was struck by the way in which the 

 conspicuous yellow Terias ]u(xlIjc, L., disappeared when it 

 settled on a low shrub with oval leaves fading to a yellow 

 tint, the rounded form of the wings aiding its concealment, "f 

 But the most convincing case that has come under my own 

 observation was a large yellow butterfly (I had no net 

 but think it was probably Catoj)silia catilla, Cr.) which I 

 saw in the garden of the University of Bombay. I saw 

 this settle again and again, invariably in a small shrub 

 with yellow leaves. The very conspicuous fly would 

 vanish suddenly, and it was only after several attempts 

 that I succeeded in getting a glimpse of it when settled, so 

 strong was the protective resemblance.^ 



In an analogous S. African case I am able to supply 

 fuller details : — 



Eronia deodora, Hlib., is a common Natal Pierine. Few 

 insects are more conspicuous in the net than this beautiful 

 fly with its combination of creamy-white, jet black and 

 deep yellow, and one might well wonder how it could 

 possibly manage to hide itself. I watched it settle once 

 upon the ground, and strangely enough it was not con- 

 spicuous when its wings were closed and the brilliant 

 yellow of the under-side was fully exposed to view. Then 

 I twice saw it settle on grass ; when the wings were half 

 open it was very conspicuous, but when they were closed 

 it was far otherwise. Four times I saw specimens go to 



* Proc. Ent. Soc. Lond., 1904, p. Ixxv, and Proc. Ent. Soc. Lond., 

 1905, p. Ixxiii, and the interesting discussion following the latter 

 paper. 



t Trans. Ent. Soc. Lond., 1905, p. 69. 



X Trans. Ent. Soc. Lond., 1905, p. 107. 



TRANS. ENT. SOC. LOND. 1906. — PART I. (mAY) 8 



