183 



arising out of a proper interpretation of the generic 

 theory. How far I have succeeded in elucidating the 

 several points which I proposed to examine^ is a problem 

 which must be solved by others ; meanwhile, if I have 

 failed at times to interpret what seems scarcely to admit 

 of positive proof, I shall at least have had the advantage 

 of propounding the enigmas for discussion, and of so 

 paving the way for future research. We must remember, 

 however, that, where certaiuty is not to be had, proba- 

 bility must be accepted in its stead j or, as an old writer 

 has well expressed it : " That we ought to follow pro- 

 bability when certainty leaves us, is plain, — ^because it 

 then becomes the only light and guide that we have. 

 For, unless it is better to wander and fluctuate in abso- 

 lute uncertainty than to follow such a guide ; unless it 

 be reasonable to put out o\ir candle because we have not 

 the Hght of the sun, it must be reasonable to direct our 

 steps by probability, when we have nothing clearer to 

 walk by*". 



What my chief aim ia the present treatise has been, 

 wiU be easily perceived,— namely, to substantiate, as 

 such, those elements of disturbance (on the outward con- 

 tour of the Annulose tribes) with which the physical 

 world does everywhere abound : and, thereupon, to pro- 

 voke the inquiry, whether entomologists, as a mass, have 

 usually taken them into sufficient account, when de- 

 scribing as "species," from distant quarters of the 

 globe, insects which recede in only muiute particulars 

 * Religion of Nature Delineated, p. 103. 



