CLEWS IN NATURAL HISTORY. 19 



tion has been extreme, but there can be no doubt that the ancestors of 

 the beetles with modified wings possessed fully developed appendages ; 

 otherwise we must regard the order of nature as being one long string 

 of strange and incoherent paradoxes. Mr. Darwin has given us some 

 instructive hints regarding the modification of beetles' wings and feet 

 in his remarks on the effects of the use and disuse of parts in the ani- 

 mal economy. Kirby, the famous authority on entomology, long ago 

 noted the fact that, in the males of many of the dung-beetles, the front 

 feet were habitually broken off. Mr. Darwin confirms the observation 

 of Kirby, and further says that in one species ( Onites apelles) the feet 

 " are so habitually lost that the insect has been described as not having 

 them." In the sacred beetle (Ateuchus) of the Egyptians, the tarsi 

 are not developed at all. Mr. Darwin remarks that necessarily we can 

 not, as yet, lay over-much stress upon the transmission of accidental 

 mutilations from parent to progeny, although, indeed, there is nothing 

 improbable in the supposition ; and, moreover, Brown-Sequard noted 

 that, in the young of Guinea-pigs which had been operated upon, the 

 mutilations were reproduced. Epilepsy, artificially produced in these 

 latter animals, is inherited by their progeny. " Hence," says Darwin, 

 " it will perhaps be safest to look at the entire absence of the anterior 

 tarsi (or feet) in Ateuchus, and their rudimentary condition in some 

 other genera, not as cases of inherited mutilations, but as due to the 

 effects of long-continued disuse ; for, as many dung-feeding beetles are 

 generally found with their tarsi lost, this must happen in early life ; 

 therefore the tarsi can not be of much importance, or be much used by 

 these insects." 



The beetles of Madeira present us with a remarkable state of mat- 

 ters, which very typically illustrates how rudimentary wings may have 

 been produced in insects. Two hundred beetles, out of over five hun- 

 dred species known to inhabit Madeira, are " so far deficient in wings 

 that they can not fly." Of twenty-nine genera confined to the island, 

 twenty-three genera include species wholly unable to wing their way 

 through the air. Now, beetles are frequently observed to perish when 

 blown out to sea ; and the beetles of Madeira lie concealed until the 

 storm ceases. The proportion of wingless beetles is said by Mr. Wol- 

 laston to be " larger in the exposed Desertas than in Madeira itself " ; 

 while most notable is the fact that several extensive groups of beetles 

 which are numerous elsewhere, which fly well, and which "absolutely 

 require the use of their wings," are almost entirely absent from Ma- 

 deira. How may the absence of wings in the Madeiran beetles be ac- 

 counted for ? Let Mr. Darwin reply : " Several considerations make 

 me believe that the wingless condition of so many Madeira beetles is 

 mainly due to the action of natural selection, combined probably with 

 disuse. For during many successive generations each individual beetle 

 which flew least, either from its wings having been ever so little less 

 perfectly developed, or from indolent habit, will have had the best 



