( xviii ) 



very desirable that further experiments of an exhaustive 

 character should be tried on the relation of moisture and 

 dryness, carefully dissociated from temperature, to dimorphism. 

 Though the dimoi-phism in the South African species of Precis 

 — to take a striking example — was quite as great as the 

 seasonal dimorphism of the well-known Araschnia levana, the 

 two different forms of it did not appear so exclusively asso- 

 ciated with the different seasons as was the case with the 

 latter species, the two forms of the Precis being so frequently 

 found together. Perhaps this was because the two seasons — 

 the wet and the dry — were not usually in tropical and sub- 

 tropical countries so sharply differentiated from each other 

 as were the winter and summer seasons in the temperate 

 regions. As regards Dr. Dixey's paper, he thought it an 

 extremely valuable one in bringing up to date the existing 

 knowledge on the subject, in giving the reasons for the con- 

 clusions he had arrived at with sufficient fulness to enable 

 others to appreciate them, and in summing up these conclu- 

 sions so that they might remain in the memory and form so 

 conveniently the groundwork for the further investigation of 

 this and allied questions. 



Professor E. B. Poulton expressed his opinion that by 

 breeding species through, Mr. Marshall had proved that one 

 form gives rise directly to the other ; the pairing of the two 

 forms being a biological test of very considerable value. 



Colonel SwiNHOE, Dr. Jordan and Mr. F. DuCane Godman 

 also joined in the discussion. 



Professor E. B. Poulton, F.R.S., read a paper on " Mimicry 

 illustrated by the Sanger-Shepherd three-colour process," 

 supplementary to his paper read at the last meeting of the 

 Society. 



April 16th, 1902. 



The Rev. Canon Fowler, M.A., D.Sc, F.L.S., President, in 

 the Chair. 



Election of Fellows. 

 Mr. James Roland Cuarnley, of Howick House, Howick, 

 near Preston, Lanes., and Mr. A. T. Gillanders, of Park 

 Cottage, Alnwick, were elected Fellows of the Society. 



