MIMICRY AND PROTECTIVE RESEMBLANCE. 



29 



inaccurate, and may lead to erroneous deductions. We have, 

 however, sufficient actual observations to prove that there must be 

 a great deal of significance in many of the resemblances and other 

 apparent means of protection, even though that significance may 

 have been exaggerated in some instances. 



1. The assimilation of colour to environment is found running 

 through the whole animal kingdom, and is especially marked in 

 large numbers of Coleoptera, more particularly in those that live 

 on or about wood or bark. We find the best instances among the 

 Longicornia and Khynchophora, whole groups of which closely 

 resemble the bark of the trees on which they live. A striking 

 case of this kind of cryptic resemblance is found in the large and 

 handsome African Longicorn, Petrognatha gigas ; not only does its 

 upper surface resemble dead velvety moss such as is found on 

 tree-trunks, but its long antennae are exactly like dry tendril-like 

 twigs. The same kind of protective resemblance is found in 

 Saperda, Lamia, and other genera ; while the weevils belonging to 

 the genus Lithium (from Madagascar) so closely resemble the 

 lichen-covered twigs on which they live that they can hardly be 

 seen by an unskilled observer, even when pointed out. Several 

 Cicindelldje are exactly adapted to their environment, and can 

 hardly be distinguished from it unless in motion ; and there are 

 very few groups in which these resemblances do not occur. Many 

 of the weevils fall and feign death at the least alarm, and as they 

 fold their legs and rostrum closely on the body, they look like 

 small seeds or bits of dry earth, and easily escape observation 

 This cryptic folding of the limbs and feigning death is also found 

 among the ByrrhidyE and certain sections of the Staphylinid^:, 

 and is a very effective method of protection. 



2. Many beetles which are distasteful exhibit bright warning 

 colours, which render them conspicuous, and thus serve to ad- 

 vertise their unpleasant qualities. Among these may be especially 

 mentioned the Coccinellld^;, Telephorii)^:, and Lyctdjs. Others 

 adopt warning attitudes, such as Ocypus olens, Broscus, Anthia, etc. ; 

 it must he remembered that there is always some actual means of 

 defence behind these colours and attitudes, consisting in the power 

 of emitting uupleasant secretions or inflicting a severe bite, in 

 case the warning is neglected. The question of warning sounds 

 is a very interesting one, but at present very little is known 

 about it. Mr. Guy Marshall, however, has proved that both a 

 kestrel and a baboon showed evident alarm at the stridulation of 

 a Longicorn beetle. 



3. Distasteful insects are often imitated by edible species be- 

 longing to the same or a different order. I have before given a 

 considerable number of instances of this mimicry in the case of 

 the Coleoptera (Proc. Ent. Soc. Lond. 1901, p. lij, and need not 

 here recapitulate them. Occasionally not only the appearance but 

 the general habits and movements of the insect are copied, as in 

 the case of the wasp-like Longicorn, Clytus arietis, which, unlike 

 its usually sluggish relatives, runs swiftly up and down the leaves 



