278 HALF HOTJRS WITH IXSECTS. [Packard. 



All the cases hitherto given are examples of unconscious 

 mimicry, and in man}', if not most, cases the effect of cli- 

 matic and other physical causes, resulting in a general har- 

 mony of hue and form which adapts all animals to the 

 world in which they live. But there are a few cases known 

 in which it is difficult not to believe that at some time in the 

 life of the species there was a conscious intention to deceive. 

 I refer to the trap door spiders and other forms which curi- 

 ously conceal the enti'ance to their holes with the manifest 

 design of hiding it from their enemies or of using it as an 

 ambuscade. I would refer the reader to Moggridge's capital 

 work on " Harvesting Ants and Trap Door Spiders," for 

 much curious and reliable information regarding the habits 

 of these spiders. Like our trap door spider, Mygale (Fig. 

 62), its allies in southei'n Europe excavate deep tunnels in 

 the earth ; they seem to take unusual pains to conceal the 

 entrance from their enemies. The hole is usually situated 

 in moss and small ferns, etc. After the door is made the 

 top is actually planted with bits of moss and small plants, 

 so that it is often impossible for the practised e3-e to detect 

 the trap door. Moggridge remaiks that the moss thus 

 transplanted by the spiders "grew as vigorously', and had 

 in every way the same appearance, as that which was rooted 

 in the surrounding earth, and so perfect was the deception 

 that I found it impossible to detect the position of the 

 closed trap even when holding it in my hand. There can be 

 no doubt that many nests escape observation in this way, 

 and the artifice is the more surprising because there is strong 

 reason to believe that this beautiful door-garden is deliber- 

 ately planted with moss by the spider, and not the effect 

 of a mere chance growth." The evidence he adduces is 

 strongly confirmatory of this view. In the nests of other 

 spiders he tells us that "it is rare to find any of the larger 

 mosses or lichens growing upon them ; but, as if to compen- 

 sate for this deficiency, a variety of foreign materials are 



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