XVI INTRODUCTION. 



pendence that is to be placed on colour alone in discriminating 

 species *. And that form and markings are supposed to be incon- 

 stant, the following observation on Cicindela hybrida of DeJean 

 sufficiently testifies : — " I feel satisfied, from the variation in form 

 and markings, that Ci. riparia and Ci. aprica are only varieties of 

 Ci. hybrida f ." In fine, it may be remarked that even the pre- 

 sence or absence of particular organs is not always indicative of 

 specific diff'erence : e. g. Clivinae Fossor and collaris, the Dromii, 

 Patrobi, &c. the species of which are sometimes winged, at others 

 apterous. 



From my experience I conceive that, where an insect differs from 

 its nearest congener by some trifling variation of form |, combined 

 with a diversity of sculpture, dissimilar bulk, or prevalent discre- 

 pancy of colour, either in the disposition of particular markings 

 or in an universal change, we are perfectly justified in consider- 

 ing such examples as distinct species, unless we are enabled by 

 experience to show incontestibly that such is contrary to nature, 

 as in the examples of the Donaciae before alluded to, and in several 

 of the species of Coccinellae and Cicadae, as hereafter united in the 

 synonymy. Such principles have guided me in my endeavours to 

 discriminate the indigenous species, as given in the following 

 pages : but to expect that I should invariably be correct in my 

 ideas respecting their real distinction, I need not remark would be 

 absurd ; although it is observed in the " Horee Entomologies," that 

 " in describing species, each of which Nature has manifestly insu- 

 lated, a failure in precision denotes an inability to seize their cha- 

 racteristic marks — it is in short a glaring fault." But I think if the 

 learned writer of the above paragraph had been better acquainted 

 with some of the indigenous groups, especially such genera as 

 Agrotis, Cucullia, Peronea, &c., he would at least have altered the 

 concluding sentence ; for, as Mr. Kirby with propriety observes, 

 " As we do not know the value and weight of the momenta by 

 which climate, food, and other supposed fortuitous circumstances 

 operate upon animal forms, we cannot point out any certain dia- 

 gnostic by which in all cases a species may be distinguished from 

 a variety; for these characters that in some are constant, in others 

 vary." 



* One consequence of assuming colour to be indicative of specific dis- 

 tinction has been to falsify physiological facts. Marsham, p. 169, says, 

 " Ex coitu Coccinellarum inter omnes familias promiscuo, varietatcs plu- 

 riniae ortce sunt." Whereas this apparent promiscuous intercourse of tlie 

 families (sections) arises entirely from regarding the mere varieties, dif- 

 fering in trifling spots of colour, as distinct species, and distributing tliese 

 varieties, as Marsham has done, into different sections, according to their 

 colour. 



f Curtis, No. I. second edition ;— a writer who in other places considers 

 form as conclusive of specific difference. 



J Considerable diversity of form is rather indicative of sectional or ge- 

 neric difference than of specific. 



