86 ON THE ORIGIN AND [CHAP. 



ones, and the same is true of the Acalephs as far as 

 these phenomena have been followed and compared 

 among them/' Indeed, the accomplished authors 

 from whom I have taken the above quotation, do 

 not hesitate to say 1 that " whenever such compari- 

 sons have been successfully carried out, the result is 

 always the same ; the present representatives of the 

 fossil types recall in their embryonic condition the 

 ancient forms, and often explain their true position 

 in the animal kingdom/' 



Fossil insects are unfortunately rare, there being 

 but few strata in which the remains of this group 

 are well preserved. Moreover, well-characterized 

 Orthoptera and Neuroptera occur as early as the 

 Devonian strata ; Coleoptera in the Coal-measures ; 

 Hymenoptera, Hemiptera, and Diptera in the Jur- 

 assic ; Lepidoptera, on the contrary, not until the 

 Tertiary. But although it appears from these facts 

 that, as far as our present information goes, the 

 Orthoptera and Neuroptera are the most ancient 

 orders, it is not, I think, conceivable that the latter 

 should have been derived from any known species of 

 the former ; on the other hand, the earliest known 

 Neuroptera and Orthoptera, though in some respects 

 less specialized than existing forms, are as truly, and 

 as well characterized, Insects, as any now existing ; 

 nor are we acquainted with any earlier forms, which 

 in any way tend to bridge over the gap between them 

 and lower groups, though, as w r e shall see, there are 

 types yet existing which throw much light on the 

 subject. 



i 1. c. p. 138. 



