198 THE CANADIAN ENTOMOLOGIST. 



profitable extent. We begin to be better acquainted with the previous 

 stages, and this acquaintance will bring these characters into more pro- 

 minence. I doubt embryological characters to be of generic value. But 

 very little is certainly known about them, and nothing known is ready for 

 our use. The parts serving for propagation have probably a higher value 

 than generic characters. Characters for genera should be of a co-ordinate 

 value. I think it is obvious that a genus should never be accepted if its 

 characters are not satisfactorily given, and that genera based on the mere 

 specification of a type should never be accepted. 



CORRESPONDENCE. 

 Dear Sir, — 



In the early part of June I found on the Wax-Myrtle ( ' Myrica cerifera ) 

 three larvae unknown then to me. I regret now that want of time pre- 

 vented me from making an accurate description of them, but my notes 

 simply say : " Looks like a Geometra — may be small Catocala ; prettily 

 marked with dark grey ; central segments underneath white or light 

 grey." 



Only one of the caterpillars produced an imago, and this proved to be 

 Catocala badia. It was about fourteen days only in the chrysalis state, and 

 I am now forced to the conclusion that C. badia must be double brooded. 



W. V. Andrews. 



P. S. — -From what I have observed of the larval habits and appearance 

 of Catocala, I am convinced that this genus should be very close to 

 Geometra. W. V. A. 



Brooklyn, July 7th, 1876. 



extract from a letter. 

 Dear Sir, — 



As an example of retarded development, let me mention that three or 

 four years ago I laid aside some old cocoons of Samia cynthia, which I 

 thought were empty, and to my amazement, three splendid specimens 

 have this season made their appearance. I know that wonderful stories are 

 told about the abnormally long continuance of some Coleoptera in the 

 chrysalis form, but I never before observed a similar instance in Lepidop- 

 tera. Do you know of any ? 



