78 THE CANADIAN ENTOMOLOGIST. 



was known of their life-histories until he turned his attention to them in 

 1868. At the present time, however, it is far otherwise; for by close 

 study, diligent care, and accurate observation, he has himself worked out 

 the complete life-histories of a large proportion of the recorded North 

 American species. Moreover, many discoveries of great interest have 

 rewarded his constant efforts : The tri-morphism of Papilio Ajax and 

 Colias Eui-ythetne, the seasonal dimorphism first of Grapta Interroga- 

 tionis, then of others in the same genus, as well as the effects of cold 

 upon larvae and the perfect insects, may especially be referred to. 



There was a marked advance in Vol. II. over Vol. I. in the amount 

 of information given concerning the life-histories of the species described. 

 This is accounted for in the prefatory notice of the present part as follows : 



"When Vol. I. was undertaken, in 1868, nothing was known by my- 

 self or any one else, of eggs, larvae, or chrysalids, except of the more 

 common butterflies. As an egg or larva could but rarely be traced back 

 to a particular female, it was impossible that much knowledge could be 

 gained of the life-histories. Scarcely any advance in this respect had 

 been made, in fact, since the time of Abbott, about 1800." . . . But 

 in 1870, I discovered an infallible way to obtain eggs from the female of 

 any species of butterfly, namely, by confining her with the growing food- 

 plant . . . and from that day to the present I have so obtained eggs 

 at will . . . and have reared larvae without end. In this way, many 

 cases of polymorphism have been established, and the position of many 

 doubtful forms settled. A light has also been thrown on the limits of 

 variation in species. In every case I have preserved descriptions of the 

 several stages ... Of a large proportion, also, Mrs. Peart has exe- 

 cuted colored drawings, magnified when necessary, and my albums con- 

 tain nearly one thousand figures." 



Mr. Edwards concludes : " And so, in this Christmas time of 1886, I 

 commend Vol. III. to the good will of the friends who have made my 

 small audience for so many years." 



Surely we may go further — a long way further — than this, and com- 

 mend it not only to the few friends who have had the good fortune to 

 listen to Mr. Edwards's teaching in the past, and perhaps to catch some 

 of his enthusiasm ; but also to every Entomologist or possessor of a 

 library, whether in America or any other part of the world, who wishes to 



