n»2 



THE AMERICAN NATURALIST [Vol. XLV 



Gametic formula- arc s invested and tin- nun lit ions they im- 

 pose arc mentioned, but no breeding work was done. Whether 

 the above explanation of the behavior of grossulariata is correct 

 or not and also the correctness of the suggested formula? for 

 polytes are immaterial to the present discussion. It is now well 

 known that "mutations" do occur in the females of insects and 

 that the new characters can be transferred to the male by proper 

 breeding. But, why do the mutants of P. polytes resemble 

 greatly, even if they do not do so to such an extent as had been 

 supposed, other species ? On account of similar anatomical and 

 physiological make up; or, in this case, did the proper gametic 

 couplings once take place so that the then new female type was 

 transferred to the males (as in <jn>ssnlari<il<t ) and was there- 

 after continued with such other modifications as were necessary 

 to separate them taxonomically ? In ot her words, the mimicking 

 species came first and gave rise to the model ! 



.Mutation, in itself, is not the whole story. Granting it. we 

 must be given a reason for the mutant resembling something else 

 and while the amendment just made to l'unnett's paper may 

 carry for this case, the chances are against it and we can not 

 apply it to resemblances between species of different orders. In 

 this connection, however, there seems to be an important thing 

 which is often overlooked. It would be far more wonderful if, 

 among the thousands of new forms which have arisen, there were 

 no resemblances than it is that some of the forms are very much 

 alike. 



As Punnett and others have pointed out, the same process 

 which brought about such a close resemblance between, for ex- 

 ample, earwigs (Orthoptera) and rove beetles (Coleoptera) that 

 they are frequently mixed in entomological collections doubtless 

 caused also the resemblances (here called mimicry because an 

 advantage can be imagined) between certain flies and certain 

 stinging Hymenoptera. If « ' chance " or " environment ' ' is used 

 in the former case it is not unlikely that it applies in the latter 



