INSECTS, HARMFUL, AND OTHERWISt; 



245 



One day I found on some goldenrods what I took to be a 

 new kind of bee. It was a beautiful, gold-banded insect, and 

 I wanted it for my collection. So I captured several in my 

 cyanide bottle, taking good care not to be stung. Later, on 

 closer examination, I found 

 that this was not a bee at all, 

 but a harmless fly which had 

 put on the dress of a bee, 

 probably to make other crea- 

 tures think that it, hke the 

 bees, carried a dangerous, 

 concealed weapon. It was 

 one of the Bee-flies. 



It is not intended to in- 

 timate here that these pro- 

 tective colors and forms 

 were brought about con- 

 sciously by the insects them- 

 selves, as if they made an effort to develop along these lines. 

 It is certainly a fact, however, that they avail themselves of 

 these protective devices. 



How these advantageous characteristics arose is difficult 

 to say. They did arise, however, in the course of evolution 

 in each case, and then the law of natural selection operated 

 and, in the struggle for existence, the forms not so well adapted 

 disappeared and the fittest survived. Those that were pro- 

 tectively colored or shaped to resemble twigs, leaves, dan- 

 gerous creatures, etc., were the ones most likely to survive. 



Fig. go. Protective Coloration of a Moth. 



