operation of that disguise, but many are equipped with brilliant iridescent 

 or metallic colors — green, blue, purple, bronze-red, bronze-yellow, etc. — 

 which strongly tend to obliterate them amid and against vegetation. The 

 fact that some nocturnal and subterranean kinds as well have rather brilliant 

 metallic colors * merely reminds us how much is still to be learned about their 

 habits. But it is, as far as I know, among truly diurnal species that the highest 

 brilliancy of coloration occurs. Sometimes, as on certain tiger beetles (Cicinde- 

 lidce), etc., brilliant iridescence is combined with small, dull, sheenless spots, 

 and the effect of this combination, in a proper view, is highly obliterative, 

 particularly if the beetle is also counter shaded. Or again, iridescent brilliance, 

 in spots or stripes, may be a small factor of a soberer pattern. Innumerable, 

 indeed, are the variations of generalized obliterative pattern — 'secant,' 'rup- 

 tive,' etc., in bands, stripes, spots and mottlings — which occur among beetles. 

 Black, yellow-buff, reddish brown, and yellowish green are probably the 

 commonest colors of the bolder patterns, which are strongly obliterative 

 against most natural backgrounds, though by no means highly specialized. 

 Transverse 'secant' marks predominate in these patterns, in accordance with 

 the simple laws of 'obliteration,' already many times explained. But much 

 more subtile patterns also occur on the Coleoptera, especially among those 

 which habitually rest on the bark of trees in the daylight. Even on beetles, such 

 finely mottled and grizzled tree-bark patterns are usually accompanied by oblit- 

 erative shading, and hence are true 'picture-patterns.' If the counter shading 

 were absent, the disguise would be mimetic, making the beetle look like an ex- 

 crescence on the bark. But we do not know of any pronounced cases of this 

 kind. Some flower beetles also have full and delicate obliterative shading. Of 

 these the American Rose Chafer (Macrodactylus subpinosus) is a good example. 



But for all their frequent obliterative patterns and rich, iridescent vegeta- 

 tion-colors, the Coleoptera, as a group, are far from taking top rank among 

 * disguised' animals, or even among disguised insects. 



In the order Hemiptera there are relatively even fewer notable types of 



* Most of them, however, are black or blackish. 

 20I 



