THE SPREAD OF A BUTTERFLY IN A NEW REGION. 1183 



In 1872 we again are able to trace the forward movement of the butter- 

 fly in Canada, where it originated, and from wliich information entirely 

 fails from 18()7, when it reached Montreal, until this time. For now we 

 learn that it had passed by this time along the nortiiern shore of the St. 

 Lawrence and Lake Ontario to Belleville and Trenton, Ontario. But 

 south of the river and the lake it had pushed much farther, viz., through 

 the entire length of the state of New York, so as to invade Canada from 

 the United States ! It did not reach Port Hope, Ontario, from the east, 

 where Mr. Bethune was awaiting it ("we fully expect to see it at Port 

 Hope this year,") until July, 1873, but it appeared at Ridgeway, Wel- 

 land Co., "not in great numbers" in 1872, and at Toronto in August 

 1872. This makes it highly probable that it reached Buffalo this year, 

 of which I could not otherwise speak, as the testimony of my correspon- 

 dents is widely conflicting. Certainly it reached Brockport, for it was 

 taken there in September by Mr. David Bruce, and the next year had 

 certainly spread much farther west on the southern than on the northern 

 shores of Lake Erie. It was in this year that it reached Delhi. In Penn- 

 sylvania, though it probably reached Centre Co. in this year, it was possi- 

 bly checked in its westward spread by the Alleghanies, as we do not hear 

 of it in the western part of the state. It reached Washington early in this 

 year, but how much farther south it passed we do not know. As, how- 

 ever, we have already heard of it in Virginia, it is probable that it had 

 extended southward at something like its previous rate and we have 

 accordingly drawn our curve to correspond with this. 



In 1873, as before stated, it reached Port Hope, and "F. C. L." re- 

 ports taking his first specimen at Dunn in Haldimand Co., Ont. ; some 

 were also taken at Hamilton, where one would have looked for it the 

 preceding year from its presence then at Toronto. Mr. Mofiiit indeed 

 thinks it highly probable that it was there in the autumn of 1872, since 

 white butterflies (which without special notice he took for protodice) were 

 then swarming everywhere about flowers. This year it had entirely cov- 

 ered New York state, though there were places even in the eastern half, 

 such as Norwich, where it did not appear until this year, at least in any 

 number. It was found sparingly at Cleveland in the spring of this year, 

 but from here southwai'd our information is ))ractically a blank. We have, 

 however, two curious items : it is reported by Mr. C. R. Dodge as being 

 destroyed by parasites in Louisville, Ky., in this year, which implies that 

 it appeared there at least the year before (probably Mr. Dodge's infor- 

 mant mistook the destructive southern cabbage buttei-fly for this). 



The other is a very definite piece of information from Prof. L. R. 

 Gibbes of Charleston, who, in a recent letter to me, after mentioning the 

 year 1870 as one which was remarkable for the number of Lepidoptera 

 seen in that city, says that P. rapae (of which he possessed English exam- 



