of the Antenna of Insects. 273 



darkness, coming to the midnight lamp of him who watches 

 for moths, has antennae of enormous length. Take also the 

 kindred groups of Cerambycites and Lepturites, the former 

 nocturnal, the latter diurnal, and the same discrepancy of an- 

 tenna will be observed. In fact, illustration so crowds on il- 

 lustration, that I should weary your readers were I to write a 

 tithe of those instances which occur to me, as affording evi- 

 dence that antenna are given as tactors, and are only called 

 into full activity when the opportunity of using eyes has in a 

 great measure ceased. Tactors are capable of a much more 

 varied perception than we should on the first thought be in- 

 clined to suppose. A power may long remain dormant, if no 

 circumstances occur to call it into action. The human fin- 

 gers become both fingers and eyes to the blind. If then in 

 the human species the fingers of one individual possess pow- 

 ers, of which another can scarcely form a conception, how 

 reasonable is it to suppose that the tactors of a cricket are 

 still tactors in a grasshopper, although their employment as 

 such may never be required. The four wings of insects are 

 the instruments of flight ; yet in beetles the fore pair have en- 

 tirely given up that occupation, and are invariably employed 

 as mere covers or protectors to the hind wings, and the soft 

 and yielding abdomen: and again, the hind pair in flies have 

 ceased to bear even the semblance of wings. In the same 

 way we see the fore legs of a vast number of butterflies, (the 

 Rhopalocera suspensa), losing entirely their usual function, 

 the very obvious and important one of walking, and becom- 

 ing mere tufts, or ornamental appendages, the end and pur- 

 port of which might lead us into endless theories, were it not 

 established beyond a doubt, that they are neither more nor 

 less than legs, which the necessities of the animal has not 

 required should be perfected in the same manner as the rest: 

 yet by watching the habits and actions of this tribe of but- 

 terflies, we fail to discover any cause why they should pos- 

 sess but four legs, while the cognate group of Rhopalocera 

 succincta have invariably six; their flight is neither more 

 sustained, nor more vigorous, neither have they in any minor 

 degree the disposition to settle on flowers, or on the ground. 

 The question appears to me to be still further simplified 

 by the fact that antennae are not possessed by insects alone. 

 Crustacea are also furnished with them, and in these the an- 

 tenna seem to have reached the maximum of developement. 

 Now in Crustacea the antenna are tactors and tactors only. 

 I believe I am correct in saying, that no zoologist has ever 

 hinted at their possessing Any other office : indeed zoologists 



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