278 
HALF HOURS WITH INSECTS. [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 entrance 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 southern 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 eye to detect 
the trap door. Moggridge remarks 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 
22 
