358 . WASP STUDIES AFIELD 



presumably have been so modified as not to be all-embrac- 

 ing in its scope. 



We know that there are established instincts. It would 

 be superfluous to do more than to mention a few of the 

 most patent of these, e.g., the instinct of every species of 

 wasp to hunt certain prey; the instinct for mating; the in- 

 stinct for getting food for itself; the instinct for stinging, 

 for nest-building, etc. These are all established and funda- 

 mental instincts which will admit of no marked digression. 

 There are, however, an unlimited number of habits which 

 seem to be constant which probably are not fixed by such 

 stern necessity as those mentioned above. These may be 

 mere habits which have become fixed in the species, even 

 as our habits become fixed without either the compulsion 

 of necessity or the urge of advantage. Nevertheless, these 

 ways seem to be constant within the species and seem to be 

 followed instinctively. As examples of this condition, we 

 may note the following cases : 



The method of digging or of building is fairly constant 

 among the members of a species and is pursued instinc- 

 tively. 



The way of Benibix nubilipennis in bringing in soft, 

 delicate flies for the first meal for her young is probably 

 an act of instinct at least it will have to be so classified 

 until otherwise proved. The large chamber at the bottom 

 of the burrow of this species, also, is not so planned by a 

 knowledge of the need of the babe, nor is the work invari- 

 ably directed to this end by tropisms, but guided again by 

 instinct. The constancy with which this species closes her 

 hole when going out on a foraging trip classes this habit 

 also with instincts. The persistence of several species of 

 wasps in carrying their prey always in the same way, some- 

 times even going through the motions of dragging or tug- 

 ging at it when it is so small that it is all the while lifted 



