ADVERTISEM 



I HAVE concluded to begin a third Volume of the " Butterflies of North 

 America," and have made such arrangements that at least ten Plates may be 

 expected to appear in each year. It may be found advisable to give sixty Plates 

 instead of fifty, as in preceding Volumes, and probably three or four will contain 

 figures of eggs exclusively, for I desire to make it clear at a glance that a natural 

 genus is indicated quite as decidedly in the shape and ornamentation of the e^' 

 as in the imago. The drawings on stone will be made under the supervision of 

 Mrs. Mary Peart, and the preparatory stages of the species treated will be illus- 

 trated more fully, if anything, than in Vol. 11. 



Some surprise has been expressed that Vol. II. should have been so great an 

 advance on Vol. I. in the matter of these early stages ; but the explanation is 

 simple. When Vol. I. was undertaken, in 1868, nothing was known by myself or 

 any one else, of eggs, larv£e,.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 Abbot, 

 about 1800, and I said as much in the Advertisement which appeared with Part I. 

 Abbot represented nothing but the mature larva and pupa. His larvre, as I have 

 been told by Mr. Titian Peale, who knew him at Savannah, were brought in by 

 boys, white and black, and generally what they were was made known when the 

 butterflies came from chrysalis. 



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. 

 If the eggs are mature they will be laid. The first experiment was made with 

 Papilio Ajax, and seasonal tri-morphism established. Three described species of 

 Papilio then and there resolved into one tri-formed species. The same summ'er, 

 the seasonal di-morphism of Grapta Interrorjationis was determined ; and soon 

 after, of Grapta Comma. And from that day to the present I have so obtained 

 eggs at will, besides receiving others, of many species, from correspondents, got 



