of these insects, or of any of the insect orders mentioned in this chapter, of 

 much interest in the present connection. Such of them as are aquatic but 

 not mud-haunting are apt to have obHterative shading, more or less complete, 

 but their coloration is seldom or never highly specialized. The larvae of dragon- 

 flies are mud- and dingy-bottom-colored, counter, shaded very scantily or 

 not at all, and they are wont to lie concealed under mud or bottom-rubbish, 

 leaving only their voracious heads exposed, ready for prey. Some hymenop- 

 terous larvae (those of "sawflies," etc.) feed on leaves in the daylight, like 

 lepidopterous caterpillars, which they resemble in many points of external 

 appearance. But they have, as a rule, some active defensive (?) equipment 

 (e. g., the power of jetting out pungent liquid), and their disguising coloration, 

 in most cases, appears far less specialized than that of many caterpillars. 

 (Some of these hymenopterous larvae, indeed, in the roUed-up attitude charac- 

 teristic of them when at rest, bear a remarkable likeness to snail-shells. But 

 this is very likely a mere coincidence.) For the most part, the larvae of the 

 Coleoptera, Hymenoptera, and Diptera live hidden away from daylight and the 

 attacks of the higher animals, except such as can dig or drill for them. Hence 

 they are colorless, or monochrome, without patterns. In the case of insects 

 whose metamorphosis is incomplete, like most of the Orthoptera, the earlier 

 stages much resemble the later in their disguising coloration. 



Spiders 



Spiders (Arachnidce) assuredly rival insects in the variety and high devel- 

 opment of their disguising costumes. But we have studied them even less 

 than we have studied insects, and hence must pass them over even more briefly. 



There are wonderful developments of out-and-out mimicry among spiders. 

 Many such cases have been described by naturalists, and many, doubtless, 

 remain to be discovered. 



But 'obliteration,' not mimicry, is our theme, and obliteration is the rule, 

 not the exception, in the disguisement of spiders. The many kinds which in 



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