THE CANADIAN ENTOMOLOGIST. 135 



reason, that, within the different Sub-orders, there is great variation in this 

 respect. For instance, in the Pyralzdce we have forms almost identical, 

 such as C/iryseudenton and Cataclysia, which differ by the absence or 

 presence of simple eyes. I do not wish to follow out the argument at 

 length ; the environment seems to effect comparatively easily the sense 

 organs ; Cave-insects are frequently blind. Again the Challenger Expe- 

 dition brought up from the depths an eyeless Crustacean — WiHemoesia, 

 named for the distinguished naturalist, Dr. Willemoes-Suhm, who, unfor- 

 tunately for science, died before the " Challenger " returned to her 

 English dock. But insects aj'e now " arranged " by their physiological 

 characters, though certainly with very different results from those attained 

 by Mr. A. H. Swinton. The whole structure and proportionate parts are 

 taken into consideration, and little can be said against the observations, 

 partly original, brought together by Dr. Packard in his " Guide." And 

 Mr. Swinton himself speaks of Dr. Scudder's observations of rank in the 

 Butterflies, not based on " sense organs," and which seems to us so full 

 and satisfactory. The observations on the "Ghost-moth" are an echo 

 of Dr. Packard's remarkable paper, in which the resemblance of Hepialus 

 to the Neuropterous genus Polystichoetes was fully discussed. That the 

 Bombycidce. afford instances of synthesis has been shown by this dis- 

 tinguished pupil of the elder Agassiz, who had so remarkable an ability 

 for perceiving and weighing analogies and affinities in animals. The 

 question of rank in insects goes hand in hand with that of the origin of 

 the diverse forms. We fear that Mr. Swinton has but very partially 

 examined the subject and that his suggestions as to sense-organs are not 

 based on proper physiological studies. Not without a certain shudder can 

 we read the author's glib disposal of the question of rank in Hexapoda. 

 And his use of sense organs to <ietermine rank is open to the objection 

 that it is not thorough ; that some members of his highest groups will 

 fall into the lowest, and thus utterly forsake their " physiological asso- 

 ciates " by reason of a sudden failing of ears and eyes. "As far as I can 

 learn " is hardly to be expected as the basis of observations seriously 

 advanced; yet with these words our author disposes of " the species of 

 Hymenoptera, Neuroptera and Diptera." There is only one way to 

 accumulate facts upon this subject, and that is to trace the changes in 

 related forms, to take the dissecting needle in hand and to take down the 

 numerous memoirs already extant upon the subject and thoroughly master 

 their contents. 



