INTRODUCTION . 9 



in the case of most species, if the nest is uncovered 

 cautiously, the moving- of the material and the 

 sudden flood of light appear not to be noticed, 

 though the bees gradually realise that something 

 is wrong, and, if left long exposed, will run off in 

 search of material with which to re-cover the nest. 

 Humble-bees possess, in common with other 



Fig. 1. A, Portion of posterior margin of fore-wing of Bombus muscorum queen, 



seen from beneath. B, Corresponding anterior margin of hind-wing, seen 

 from above. 



bees, various peculiarities of structure adapted for 

 special uses .that it is hardly within the scope of 

 this monograph to describe in detail, but a few of 

 the most interesting may be here referred to. 



First may be mentioned the wing-hooks, and I 

 cannot do better than quote Bingham's description 

 of these : " The winged hymenoptera are, as a rule, 

 capable of swift and sustained flight. For this 

 purpose they possess a wonderful arrangement (one 

 of the most beautiful in nature) for linking together, 

 during flight, the fore- and hind-wings. Examined 



