characteristically seems merged into the flat plane on which it sits, rather 

 than showing its real, slightly raised form and passing for an inanimate excres- 

 cence. Of course, however, this rule has exceptions. Any such moth must 

 sometimes, especially in side view, present and profit by the mimetic instead 

 of the ehliterative aspect; and there may be some moth-costumes which have 

 been developed for full and elaborate mimicry of this kind, at the expense of 

 'obliteration.' But that this is exceptional* is amply shown not only by the 

 character of most moths' patterns, but by the complete obliterative shading 

 which their usually plump bodies bear. This can be seen to best advantage 

 on the very large-bodied kinds, notably the hawk moths (Sphingidce); but 

 — supposititious mimetic moths aside — ^there are almost no species that lack 

 it. Usually the bodies are not only counter shaded, but marked with oblit- 

 erative patterns — either such, already mentioned, as cooperate with the back- 

 ground-pictures on the wings, or bolder 'secant' and 'ruptive' patterns which 

 tend to obliterate the bodies in side view, when exposed to sight below the 

 wings. A similar service is rendered by the more or less abortive patterns 

 of the under sides of the wings, which are usually dim and imperfect counter- 

 parts of those of the upper sides. In most cases, they are normally quite 

 hidden while the moth is perching, and their frequent comparative crudeness 

 seems therefore to be in just proportion to the smallness of their use. In 

 flight they are of course exposed — though much less clearly than the upper-side 

 patterns, because masked by shadow — and they then, especially in the cases of 

 the brighter and bolder ones, have a distinct share of obliterative effect. On 

 the other hand, the prevalent paleness of the under sides of the wings must be 

 classed with obliterative counter shading. But the pattern of this part of a 

 moth is evidently of scant importance, and accordingly tends to be scantily 

 developed, compared with the upper-side pattern, and with the under-side 

 patterns of perpendicularly-folding butterflies. 



There are, indeed, perpendicularly-folding moths, just as there are flatly 

 applied butterflies, and the types of pattern are correspondingly interchanged. 



* (If there be such cases) — A. H. T. 

 236 



