8 THE entomologist's recgrd. 



t^phiwjidae can be divided according to the sexual armature into the 

 following categories — 



"1. Species that are not different from their relatives in these 

 organs . . . ." 



"2. Species which are different from their nearest relatives, but do 

 not show any marked geographical variation in the sexual armature. 

 Here belongs by far the greater proportion of the Hawk moths." 

 With regard to the difference " there is every conceivable grada- 

 tion . . . ." 



"B. Species which differ from their allies and vary in themselves 

 geographically. Geographical variation is most often met w4th, and 

 is most conspicuous, in those forms which are sedentary in habits. 

 Sluggish species with functionless mouthparts and reduced powers of 

 flight, species of which the sole function as imagines is propagation, 

 are especially liable to develop into geographical races, with differences 

 in the sexual armature. The phenomenon occurs often in Ambulicinae 

 [Smerlnthidae, auct.). The geographical differences in these 

 organs, which may or may not be accompanied by differences in 

 external features, are occasionally surprisingly great . . . ." 



In what follows many will disagree with our authors, but we fancy 

 what they mean is identical with what we have always insisted upon, 

 viz., that the sexual armature is as liable to variation within the limits of a 

 species as any other portion of the anatomy, and may vary to as 

 extreme a degree ; it only becomes of more value as a specific character 

 than any other difference, if it can be shown that the divergence is 

 great enough to render crossing hiiuiediate or mediate of the two forms 

 impossible. That the armature presents more definite differences than 

 other parts renders it more easy to consider, but not of more value as 

 a specific character. 



"It is quite erroneous to say that differences in the sexual armature 

 are always of specific value. Geographical races may be different or 

 not in these organs, and the dift'erence may be minute or conspicuous. 

 It is idle to maintain that geographical representatives are specifically 

 distinct if the sexual armature shows obvious differences. What one 

 investigator considers obvious in these organs (as well as in others) a 

 second student does not think woi-th noticing. . . . There is no 

 line of separation between conspicuous and mconspicuous differences. 

 . . . . Therefore, to say which geographical differences are specific 

 and which not, would be entirely dependent, not on the facts, but on 

 the personal view of the investigator. ... A view of specific dis- 

 tinction, making it dependent on personal opinion, must, therefore, 

 necessarily be erroneous." All perfectly true specific distinctness is, 

 no doubt, a matter of fact and not a matter of opinion, but as we can 

 only imperfectly get at the facts, we are confined to giving a personal 

 opinion about them in the great majority of debatable cases. 



The armature is also of great value for generic characters, and the 

 female armature often presents very striking characters. The 

 asymmetry of these organs is very fully discussed, the armature of the 

 penis-sheath ((wdoeai/iis) is almost always asymmetrical. There is 

 much more in this section that one would like to refer to, but we are 

 already becoming too lengthy. 



Out of the 67 plates no less than 51 are devoted to these 

 morphological details ; and as some of the plates contain nearly 60 



