302 MENTAL EVOLUTION IN ANIMALS. 



when Pompilius stung its prey in the ganglion it intended or 

 knew that their prey would keep long alive. The development 

 of the larvae may have been subsequently modified in relation 

 to their half -dead, instead of wholly dead prey ; supposing 

 that the prey was at first quite killed, which would have 

 required much stinging. Turn this over in your mind," &c. 



Now in Chapter XIV I have already given a short epitome 

 of the facts concerning the boring by humble-bees of holes in 

 corollas, and the subsequent utilization of the holes by hive- 

 bees. It will be remembered that the connection in which I 

 there alluded to the facts was that of the power of imitation 

 by one species of the habits of another — the hive-bees observ- 

 ing that the humble-bees were saving time by sucking through 

 the holes instead of entering the flowers. But the point 

 which is of importance in the present connection is the intelli- 

 gence displayed by the humble-bees in originating the idea, 

 so to speak, of boring the holes. For close observation shows 

 that they bore the holes with as precise an appreciation of 

 the morphology of the flowers, as is shown by the Sphex of 

 the morphology of spiders, insects, or caterpillars. Thus in 

 the case of leguminous flowers they bite only through the 

 standard petal, and always on the left side just over the 

 passage to the nectar, which is larger than the corresponding 

 passage on the right side. Therefore, as Mr. Francis Darwin 

 observes, "it is difficult to say how the bees could have 

 acquired this habit. Whether they discovered the inequality 

 in the size of the nectar-holes in sucking the flowers in the 

 proper way, and then utilized this knowledge in determining 

 where to gnaw the hole ; or whether they found out the best 

 situation by biting through the standard at various points, 

 and afterwards remembered its situation in visiting other 

 flowers. But in either case they show a remarkable power of 

 making use of what they have learnt by experience."* 



Seeing, then, that Hymenopterous insects are certainly 

 proved by these observations to be capable of marvellously in- 

 telligent appreciation of morphological structure, I think with 

 Mr. Darwin that these observations are most apposite to the 

 case of the Sphex. There is not, after all, so very much more 

 of this kind of appreciation required to observe the effects of 

 stinging a caterpillar between its segments, than to hit upon 

 the idea of -going outside a flower and biting a hole on the 



* Nature, Jan. 8, 1874, p. 189. 



