cxliv On the Affinities of the Pulicites. 



this difference ; that in the case of Stylops, the obscurity appears due 

 to an error of description, and to an almost total ignorance of its eco- 

 nomy, in the flea to the extremely abnormal characters of the imago. 

 From the most remote antiquity the flea has been a puzzle and a prob- 

 lem to our ablest naturalists. Still 1 cannot but regard with infinite 

 pleasure the fact, that the deliberative entomologists of the last thirty 

 years have indicated the truth, although in no instance has the prob- 

 lem been worked out. Lamarck expressly invites attention to the 

 identity of metamorphosis between the flea and certain of the Dipte- 

 ra ; Oken considered the flea dipterous ; Haliday, in a letter to Mr. 

 Curtis, published fn 'British Entomology,' indicates his having arrived 

 at a similar conclusion. " In investigating," says he, " the analogy be- 

 tween Cordyla and Mycetophila nigra on the one hand and Pulex on 

 the other, I was led to the discovery of the antennae of the latter ge- 

 nus; 1 ' in this passage the affinities of the flea are clearly indicated. 

 Burmeister again considered the flea a dipterous insect ; and Strauss 

 Durckheim, an author unhappily unknown in this country, except 

 through the admirable abstract by my late friend, Edward Doubleday, 

 and my own numerous citations in the first volume of the ' Entomo- 

 logical Magazine,' expressly asserts that the flea is nothing more than 

 a dipterous insect without wings ; Erichson, Schiodte and Siebold 

 have all expressed the same opinion. Under these circumstances my 

 position is widely different from that which I occupied in the investi- 

 gation of Stylops : then, I stood alone ; * here, I am surrounded by a 

 cloud of witnesses, the very principes of the science. 



It is not extraordinary that the characters of the perfect flea should 

 have misled our earlier systematists, for it may be observed that when 

 a law of nature is clearly pointed out, as in the instance of the varied 

 characters of insects' wings, it is almost certain to be received with too 

 abject a servility; and hence the exceptions which are sure to exist 

 are not sufficiently taken into consideration : still I am at a loss to 

 conceive on what ground two of our most respectable methodisers have 

 adopted their view of its affinities. 1 allude to Latreille and Leach ; 

 the former of whom places the flea between Pediculus and Cicindela, 

 the latter between Coccus and Papilio. These seem grave errors of 

 judgment; but an error of fact equally grave, first broached by the 

 younger MacLeay, was subsequently repeated and insisted on by M. 

 Duges, and, in spite of its most transparent fallacy, has obtained cur- 

 rency among recent compilers : I allude to the supposed presence of 



* See Supplementary Note. 



