THE CANADIAN ENTOMOLOGIST. 



Major Tulloch, F.E.S., in regard to Catopsilia pomona in Hong 

 Kong (Ent. XLVI, 205), but it would seem that neither the shorten- 

 ing of the shadow nor the obtaining of warmth will explain all 

 there is to be learned. Unless my memory serves me badly, I can 

 recall patches of roadside where Colias philodice had congregated in 

 dozens, many of them resting with their wings at a decided angle, 

 and they were not at all agreed as to the direction of the body; 

 some had the body at right angles to the sun's rays, others with 

 the tail towards the sun, others again intermediate. So the shadows 

 would be all sorts of sizes and shapes, besides which it seems 

 to require explanation how a number of shadows on a dusty or 

 muddy road would add to the conspicuousness of these sulphur 

 butterflies, so bright and attractive are they when they collect 

 in little flocks, some members of which are constantly fluttering 

 about. Of course, we can only judge this from their appearance 

 to the human eye; what natural enemies they fear is another matter. 

 My own observations being confined to a robber fly (AsilidcB) 

 catching one on the wing, and another being gobbled up by a big 

 toad, this latter victim was leaning over, and many others within 

 a few inches were erect. The idea of warmth being sought seems 

 to fail in that some of the hottest days appear to be favourable for 

 leaning over, and one flock will be found for the most part leaning 

 over, while in another perhaps only a few feet away they will all 

 be erect, while on cool days, though bright, none may be at an 

 angle. It seems that a combination of circumstances is often 

 involved, and that perhaps the brightness of the midsummer sun 

 full face is .too great and makes many of them prefer to turn their 

 profile towards it. The direction of the wind, if strong, may also 

 alTect them to some extent, so also may the direction of the road, 

 for many of the roads loved by the sulphur butterflies are full of 

 ruts and ridges made by cart and carriage wheels, and a butterfly 

 settling on such a ridge longitudinally must either stretch out the 

 three legs on one side more than the other three or he would in- 

 evitably lean over. When resting on flowers, say thistle, their 

 heads certainly point in all sorts of directions; but those that are 

 feeding should be noted separately from those that are not, for an 

 insect will do all sorts of gymnastics to get its dinner, and the 

 same remark should apply to flocks about damp patches on the 



