50 THE ENTOMOLOGIST. 



Exchanging. — Until recently my own exchange list was 

 embellished with the prevailing marks against complete series; 

 but one of my correspondents favouring me with his marked 

 list, I was much struck with his method, and at once adopted 

 it. As I think it could hardly be improved upon, I venture to 

 give particulars. Complete series are left unmarked, incomplete 

 have a cross, and a stroke is put against species unrepresented 

 in the collection, which stroke is crossed when a specimen or 

 specimens are obtained, and when a series is completed the cross 

 is surrounded by a circle. The list thus stands : Complete, no 

 mark or *. Incomplete +. None — . This is a very simple 

 arrangement, and, I think, would meet the approval of your 

 correspondents. With reference to the concluding portion of 

 Mr. Raynor's paragraph (Entom. xviii. 23), I think the secret lies 

 in the fact of the very large increase in the number of collectors. 

 At the same time I feel sure there are yet many who would feel 

 pleasure in assisting others in the manner described. Will your 

 correspondent lead the way? — E. Sabine, 17, The Villas, Erith. 



Time of Appearance of Argynnis pandora. — In the last 



number of the 'Entomologist' (p. 21) a correspondent refers to 



the time of appearance of Argynnis pandora. Most authors give 



June and July as the period when this si)ecies appears in the 



imaginal state. Some, however, as Herrich-Schaifer, only 



mention June. An example from the collection of the late Sir 



Sidney Saunders is ticketed " Yanina, June." I believe that I 



have given correctly its normal times of appearance in my work 



as referred to by Mr. Carrington. But it must be recollected 



that the evolution of the imagines in this genus is hastened or 



retarded by the forwardness or lateness of the season. For 



instance, the normal time of appearance of A. adippe in this 



district is about the middle of July ; yet in forward seasons it 



will occasionally appear nearly a month earlier ; on the other 



hand, it is sometimes the end of July before it makes its 



appearance, fresh specimens being obtainable till the middle 



of August. Almost the same may be said of Argynnis pajjhia. 



Again, altitude has a very marked effect. I have taken A. adippe 



and A. aglaia in a perfectly fresh condition at the beginning 



of September in rather elevated localities in Switzerland, 



whereas in the lower-lying places they would by that time 



have ceased to appear on the wing for a month. I think it is 



