52 THE GENESIS OF SPECIES. \Cn^T. 



uiKlergoes a sort of liquefaction of a great part of its l>ody, 

 M'liile certain patclies of formative tissue, which are attached 

 to the ramifying air-tuhes, or traclieie (and wliich patches 

 V»ear the name of " imaginal disks "), give rise to the legs, 

 wings, eyes, &c., respectively ; and these severally formed 

 parts grow together, and Iniild u]) the head and body hy 

 their mutual a])])roximation. Such a process is uidvuown 

 outside the class of insects, and inside that class it is onlv 

 known in a lew of the two-winged Hies. Now, how 

 " Natural Selection," or any *' laws of correlation," con 

 account for the gradual development of such an exceptional 

 process of development — so extremely divergent from that 

 of other insects — seems nothing less than inconceivalde. 

 ^Ir. IXarwin himself^ gives an account of a very peculiar 

 and abnormal mode of development of a certain beetle, the 

 sitaris, as described by M. Fabre. This insect, instead of 

 at ifrst appearing in its grul) stage, and then, after a time, 

 putting on the adult form, is at first active, and furnished 

 with six legs, two long antennae, and four eyes. Hatched 

 in the nests of bees, it at first attaches itself to one of the 

 males, and then crawls, when the opportunity offers, upon 

 a female bee. Wlien the female bee lays her eggs, the 

 young sitaris springs upon them and devours them. Tlien, 

 losing its eyes, legs, and antenna?, and becoming rudimen- 

 tary, it sinks into an ordinary grub-like form, and feeds 

 on honey, ultimately undergoing another transformation, re- 

 acquiring its legs, &c., and emerging a perfect beetle ! That 

 such a process should have arisen l)y the accumulation of 

 minute accidental \ariations in structure and habit, a]>pears 

 to many minds, ([uite com])etent to form an opini(jn uu the 

 subject, absolutely incredible. 



1 "Origin of Species," 5tli eilit., p. 532. 



