( cxciv ) 



poison emitted in fear," * and (2) that a dog, if a Humble Bee 

 be presented to him, " will turn away in disgust, although he 

 will readily snap at a fly." f Besides, except in the case of Social 

 Bees, the sting is only exceptionally a really formidable weapon. 

 Many Fossors hardly use the sting at all except for paralysing 

 their prey, and if they fight, prefer to trust to their mandi- 

 bles. This has been noticed especially in Philanthus. Pro- 

 fessor Poulton tells me, that he has seen a fight between 

 Workers of true "Wasps " conducted solely by means of the 

 mandibles, and aimed at cutting off the abdomen of the 

 opponent." The sting of some wild Bees, e. g. Andre7ia, is quite 

 negligible, and even that of the Hive Bee has no terrors for 

 such birds as Merops apiaster and persicus, or (according to 

 Hoffer) for swallows, or for the Fossor Philanthus, or the 

 Dipteron Asihis, or (according to Butler's observations quoted | 

 by Wallace) for lizards and frogs, which swallow them " in 

 utter disregard of their stings." 



No one, I should think, who has collected in the deserts of 

 Algeria, Egypt and Palestine can doubt, that the very pale 

 colours and shimmering silvery or golden pruinosity, so common 

 in all groups of Hymenoptera in such localities and practically 

 there only, are Cryptic characters, rendering the insects which 

 possess them inconspicuous and almost invisible § among the 

 glittering sands and pale vegetation which they haunt. Here 

 at least, contrary to the rule laid down by Wallace, we have 

 stinging Hymenoptera coloured so as to resemble — or at any 

 rate so as not to conti-ast with — "the inanimate and vegetable 

 substances " which normally surround them. 



But to retui-n to colour-characters which differ in the sexes. 

 This, I think, is not often the case with " metallic " colours (as 

 blue, green, violet, etc.) which are due, not to pigment, but to 

 interference. Such colours, however, are exceptional in the 

 Palaearctic Fauna, and I hesitate to say much of them with- 

 out knowing how far they yield sexual characters in Exotic 



* Sladen, The Humble Bee, p. 13. f Ibid., p. 115. 



X On Natural Selection, p. 122. 



§ Professor Poulton tells me of a remark made to him by the late 

 E. Saunders that the silvery or golden faces of such insects ( 6 6 especially) 

 peeping out or emerging from holes in the glaring sand would surely be 

 effective in concealing them. 



