PROCEEDINGS, lOlS 19 



No. of Specimens 



1. Uniform dark chocolate brown, markings indistinct 18 



2. Very dark, with the band on outer margin and the 



reniform and orbicular spots showing distinct but dark 9 



3. Dark, with the same markings lighter and more con- 



trasting 13 



Total 40 



The female parent of the brood lielonged to group No. 2. It is 

 curious that there should be fewer of this type than the others. 



A REVISION OF THE BRITISH COLUMBIA SPECIES OF THE 

 GEOMETRID GENUS HYDRIOMENA HUB. 



By E. H. Blackmore, Victoria, B.C. 



During the past four years I have endeavoured to try and straighten 

 out this most difficult and perplexing group, as far as it concerned our 

 British Columbia species. I have given papers on this genus at some 

 of our previous meetings, bringing the changes up to date as our knowl- 

 edge became more extended. In consequence of further additional 

 research, other changes have been made which brings this particular 

 genus pretty near perfection. What has made this genus so perplexing 

 in the past is the fact that many species which could not be conveniently 

 placed in any other genera, were all dumped in here, witli the result that 

 there was a heterogenous mass of species which bore no apparent 

 relationship to each other, either in maculation or generic structure. 



In 1892, Mr. Meyrick, of London, England, published a "Classifica- 

 tion of Geometrina of the European Fauna" (Trans. Ento. Socy. London 

 1892, Part 1, pp. 53-140), in which he endeavoured to arrange the family 

 on the basis of invariable structure. This classification was not entirely 

 adopted, as he had not taken into accovmt the known existence of inter- 

 mediate forms in nature. The strictest application of his fundamental 

 rules of classification, made some of his genera, especially the one we 

 have under consideration, cover almost sub-family differences. 



The Rev. Geo. Hulst, some four years later, published a "Classifica- 

 tion of the Geometrina of North America" (Trans. Am. Ent. Socy., 

 Vol. XXIII., pages 245-386), and while following Meyrick's classification 

 in the main, he made several changes, notably in this genus Hydriomena, 

 separating from it five other genera which Alcyrick had placed with it, 

 viz. : Mesoleuca, Caenocalpe, Triphosa, Euchoria and Gypsochroa. Even 

 then, Hulst admitted that he had drawn an artificial line in this genus, 

 as he says : 



