THOUGHTS ON SPECIES. 165 



during it, but its species, and at the same time its genus, 

 family, order and class. 



There remains still another element of disorder to be taken 

 into consideration, which results in the production of a variety 

 known as the hybrid. 



The entire question of hybridity stands in need of a careful 

 re-examination. Conclusions have been promulgated and 

 received as the general laws upon this subject, and are usually 

 regarded as decisive, although I cannot conceive why its in- 

 vestigation should be looked upon as exhausted. Probably 

 no other portion of natural history affords opportunities so 

 convenient to pursue this study as Entomology, and I hope 

 some student will follow it in the proper philosophic spirit. 



The variety resulting from hybridity is generally regarded 

 as transient, displaying the specific characteristics of both 

 parents ; as incapable of continuing itself with one of its 

 own kind, but fertile with the parent stock, and of course 

 reverting to it. Whether it is possible to establish a per- 

 manent variety, either by the intermixture of a hybrid and 

 a species closely allied to the parent stock, or by any other 

 means, is an interesting but undetermined question in Ento- 

 mology. Dr. Hagen, of Germany, has recently displayed 

 much interest in this subject, but has not investigated it 

 experimentally, so far as I am informed. The few cases 

 of hybridity that have been recorded have taken place in 

 nature, or have been the result of mere individual caprice 

 on the part of experimentalists and without reference to the 

 determination of any of the numerous questions to which it 

 gives rise. Hence, hybridity can be noticed here only as 

 a cause of variation in insects, and how far it may have 

 complicated, or may be capable of complicating, the determi- 



