24 
specialised condition, and how, at the same time, an increase in the 
branches and complication of a nervure may be a recent form of 
development, and represent a still more specialised condition. 
That a structure, showing such distinct modification as the 
neuration, must be of the greatest use in helping us to come to correct 
conclusions when its values are properly understood, must be 
conceded ; one feels though, at present, that the correct meaning of 
detailed neurational modifications has not yet been thoroughly grasped. 
The ease with which nervures may be counted, the readiness with 
which simple numbers may be applied to nervures which have no 
homologies with each other, have provided a ready pitfall for most 
lepidopterists who have superficially glanced at what is, in reality, one 
of the most complicated and difficult branches of entomological study. 
I think I have said enough to show you the lines on which recent 
authorities have worked. Kellogg, Comstock, Packard, Hampson 
and others have taken up other lines of study. It is the union of all 
these various lines, the collection of these apparently heterogeneous 
materials into a simple homogeneous unity which must give us our 
final ideal system of classification. 
Here a word of warning is necessary. In my paper, “ An attempt 
to correlate the results arrived at in recent papers on the Classification 
of Lepidoptera ” {Trans. Ent. Soc. Land., 1895, pp. 343-362) I 
wrote:—“ No scheme based on a single set of characters, belonging 
to only one stage, can possibly be even approximately perfect. It is 
possible to conceive that, especially in those Orders where the method 
of life differs so greatly in the various stages and different means of 
defence and protection are thus rendered necessary, an insect may be 
very greatly modified in one particular stage without any corresponding 
modification in the other stages being at all necessary. It may 
happen to be of advantage for the larva to be of a generalised type, 
and for the imago to be much more specialised, or vice versa. It 
follows, if this he granted, that no scheme of classification that is not 
founded upon a consideration of the structural details and peculiarities 
of the insects in all their stages can be considered as really sound, 
or as founded upon a natural basis. It is also evident that the results 
of the various systems—whether based on oval, larval, pupal or 
imaginal characters—must be compared and the sum total of 
evidence brought together, if a satisfactory result is to be obtained. 
If these results agree, then it is clear that the conclusions arrived at 
are sound; but if the characters from one stage appear to suggest a 
different result from those obtained from another, it is evident that 
fresh observations and comparisons need to be made, and the 
differences to be explained before any adequate scheme can be 
formulated.” 
Surely this is logical and reasonable, and yet failure to understand 
these simple principles has led to the publication during the last few 
weeks of the most amazing hotch-potch of advanced science, and con¬ 
servative reaction offered to the scientific world. Neither larval 
tubercles, pupal segments, neuration, or any other character is 
sufficient alone to give us a natural system, Either will give us a dead 
