SYSTEM OF INSECTS. 367 



either concatenated like a chain, or placed separately at 

 small intervals from each other. It may run either in a 

 right line, or deviate from it in various ways. It appears 

 to be the opinion of most modern Physiologists, that the 

 series of affinities in nature is a concatenated or con- 

 tinuous series ; and that though an hiatus is here and 

 there observable, this has been caused either by the an- 

 nihilation of some original group or species in conse- 

 quence of some great convulsion of nature, or that the 

 objects required to fill it up are still in existence but 

 have not yet been discovered a : and this opinion is found- 

 ed on a dictum of Linne, Natura. . .saltus nonfacit b . If 

 this dictum be liberally interpreted, according to the 

 evident meaning of the word saltus, few will be disposed 

 to object to it ; since both observation and analogy com- 

 bine to prove that there must be a regular approxima- 

 tion of things to each other in the works of God ; and 

 that could we see the whole according to his original 

 plan, we should find no violent interval to break up that 

 approximation : but if it be contended, that in this plan 

 there is no difference in the juxtaposition of the nearest 

 groups or individuals, and never any interval between 

 them, I think we are going further than either observa- 

 tion or analogy will warrant. Were this really and 

 strictly the case, it seems to follow that every group or 

 individual species must on one side borrow half its cha- 

 racters from the preceding group or species, and on the 

 other impart half to the succeeding c . But one of the 



a W. S. MacLeay in Linn. Trans, xiv. 54. 



b Linn. Syst. Nat. i. 1 1 . c Qu. Whether every real 



species or group has not some one or more peculiar characters which 

 it neither derives from its predecessor nor imparts to its successor in 

 a series ? 



