NOTES ON THE GENITAL ARMATURE. 41 



My mounts, many hundreds in number, are entirely at the disposal 

 of anyone who cares to travel down to Mucking to examine them, and 

 I have no doubt but Mr. Pierce will, with equal pleasure, say the same. 

 More than this I am willing (within reasonable limits of course) to 

 mount for any one who wishes it, any Geometrid genitalia which may 

 be called in question, on condition that at least two males and one 

 female be sent; in order that I may have an opportunity of making 

 apparent, the superiority of the Vertical over the Profile-position, 

 Again, I have no doubt but, Mr. Pierce will be equally willing to do 

 the same. Or, I will submit such mounts to Mr. Tonge, Mr. Noad 

 Clark, or other Photographic expert (if such there be) that he may 

 make a photograph free from bias. Or again, I will submit a set of 

 selected mounts for examination by any Entomological Society. 



I do not think that I can do more than this to prove my own 

 conviction as to the honi'sti/ of the figures in question. 



As I am thus drawn into this controversy, I may, perhaps be 

 allowed to place on record my own opinion upon some of the pomts in 

 question, taking such in the order followed by Mr. Bethune-Baker. 



1. PJiotof/rap/nj. I notice that this method of reproduction is not 

 preferred by all scientists. In the Tra^hsactions and ['roceedini/s of the 

 Kntomological Societi/ of London, 1912-13, I find (excluding colour 

 plates, plates of imagines, landscapes, etc.), 50 drawings to 20 

 photographs. In those for 1913-14, 15 drawings to 13 photographs, 

 and in the current Volume, 13 drawings to 30 photographs, making 

 for the period covered, 78 drawings to 75 photographs. It may be 

 said that these plates represent the views of but very few individuals, 

 but there stands the fact. I remember that our dear old friend J. W. 

 Tutt, just before his fatal illness, having before him the completed 

 photographic plates of my series of Hydra'cias, deliberately called in 

 the aid of a hand artist to produce understandable pictures. My own 

 objections to the Photographic method of illustration are: — 



(1) That each figure represents a single individual, perfect or 

 imperfect. 



(2) That it is necessary to flatten unduly (squash) the specimen 

 to be photographed. 



(3) That it is not possible to make a detail picture of thick chitin 

 and thin integument with the same exposure. One or other must be 

 sacrified unless the object be unduly thinned or " squashed." 



I emphasize the flattening of the specimen, which is necessary to 

 secure, as far as possible, that all the object shall be in the focal plane 

 and thin enough to agree with the focal depth, of even the best of 

 microscope objectives. 



(4) That it is true that superposition of several organs does obscure 

 the true structure. I can produce a mount in which it would be quite 

 possible to have, in the profile 12, separate surfaces at least. 



2. The profile /iDsition. How Mr. Bethune-Baker can claim this at 

 the more natural position I cannot imagine. Is it natural for a 

 Lepidopteron to have its final segments pressed flat with a fold all 

 along the dorsal and ventral centres? The NatKral iiositi(»i (in 

 life I presume) depends entirely upon the point of view of the 

 observer, and upon the conditions. If I look upon the side, it is true 

 that I get a profile view, but the parts are riot squeezed together. If 



