( 13 ) 



" The above groups hardly represent the true predominance 

 in numbers of the Crenis, at any rate at this time of the year 

 (the beginning of the rains). Last April and May at the 

 xvii] 



end of the rains I found both models and mimic scarce, but 

 Concordia the more common of the two. This, however, was 

 in lower and flatter country, whereas the Crenis, especially 

 the large blue ones, are particularly addicted to hills." 



Dr. F. A. DiXEY said that to deal with Mr. Marshall's 

 criticisms point by point would require another treatise on the 

 same scale as the one now before them. He therefore pro- 

 posed to reserve any detailed comment for a future occasion. 

 In thev meantime he wished to thank Mr. Marshall for his 

 courtesy in allowing him to see the paper before it had been 

 communicated to the Society. He welcomed the opposition 

 therein offered to his own view, because no theory could claim 

 to stand on a firm basis until it had been well scrutinised and 

 had run the gauntlet of adverse criticism. The author of any 

 hypothesis that had been successfully attacked had always the 

 satisfaction of feeling that at least he had helped to arouse 

 interest and to stimulate inquiry ; and in any event the cause 

 of truth would be the gainer. No doubt they had from Mr. 

 Marshall as good a statement of his side of the case as any one 

 could make, and if his objections could be satisfactoi'ily met, 

 as in the speaker's opinion they could be, it was not likely that 

 any more formidable assault would have to be faced. It would 

 naturally be expected that he should join issue with Mr. Mar- 

 shall, and this he undertook to do when the time came ; 

 meanwhile he would only make the general remark that ajjriori 

 reasoning in similar matters had before now been known to 

 fail, even when aided by mathematical processes as unimpeach- 

 able as those of his present critic. 



xxvi] 



Wednesday, April 1st, 1908. 



Tongue of an Ochromyia. — Professor Poulton exhibited 

 a preparation of the tongue of the fly Ochromyia jejuna, made 

 by Mr. E. Ernest Green, F.E.S., and gave an account of some 

 fresh observations recorded by him. These new facts, bearing 



