The Zoologist— January, 1868. 1039 



Of these false, or as they are termed scientific, dichotomies there are 

 two preeminently popular. By this principle Lepidoptera are divided 

 into Rhopalocera and Heterocera. ; animals into vertebrate and ^verte- 

 brate. Let us glance at these dichotomies only for a moment. First, 

 that of Lepidoptera into Rhopalocera and Heterocera,— Rhopalocera 

 conveys in its very name the expression of a character, and Hetero- 

 cera. equally implying the want of a character. Secondly, an exactly 

 parallel instance is the dichotomous division of animals into vertebrate 

 and ^vertebrate ; the haute ecole of Science roll out these terms with 

 great power of voice and immeasurable self-complaisance ; but Nature 

 fails to acknowledge them : as well might we divide animals into hairy 

 and not-hairy, or feathered and raoZ-feathered : such terms as verte- 

 brate, hairy and feathered express positive characters, but no group 

 can be based on the wora-possession of these characters— a fact that 

 must be only too obvious to every one who gives the subject a fair 

 share of consideration. 



Not only do these dichotomies, founded on a positive and a negative, 

 find no support in Nature, but they have another fault equally embar- 

 rassing to the student: they give a measure— a small but notable 

 measure— of character to one moiety of the pair, yet leave the other 

 moiety a perfect chaos, and do not afford us the slightest clew to the 

 arrangement or subdivision of its contents. 



Now exactly such dichotomies as we find in kingdoms— I accept 

 the term as prescriptive, not for its merits— exactly such do we find in 

 all minor divisions known as provinces, classes, orders, families, genera 

 and so forth, until we arrive at those species where the present inquiry 

 properly begins; and here I would extend a word of caution to those 

 who really desire to investigate the subject: let no one assume the 

 universality of the law, since all that can be done in our present state 

 of ignorance is to follow out these dichotomies where we see traces of 

 their existence, and thus acquire such an amount of knowledge as 

 shall dissipate that ignorance, and it is of the utmost importance that 

 we take nothing for granted, that we assume nothing, that we test 

 everything by repeated experiment. 



I wdl select half a score examples from as many families to illustrate 

 my meaning, and bring it more immediately under the notice of my 

 readers, aud I wish to invite especial attention to the fact that the 

 moieties of each pair are produced under precisely parallel circum- 

 stances ; that climatal or geographical or seasonal conditions have no 

 influence over them ; that they may be produced at the same hour, 



