OF PIERIS RAPAE IN NORTH AMERICA. (J7 



ercd the area upon tlie map over which P. venosa is known to extend with close cross rul- 

 ing, and that which it may probably also occupy with more open ruling-. It will thereby 

 be seen that the introduced P. rapae is rapidly progressing toward its near of kin. It 

 may well be believed that if P. rapae has in the last five years crossed the high plains 

 of Kansas and Nebraska on its westwai-d march, as it has done, the butterfly considered 

 by Mr. W. H. Edwards and others as Pieris rapae, which has been on the Pacific coast 

 since 1859, W'Ould, in more than a quarter of a century, if it were P. rapae, certainly have 

 extended eastward across the less arid countrj' along the northern boundary of the United 

 States to a proportionably longer distance, — w^hich it certainly has not done. It there- 

 fore fails in one characteristic of that ravenous and destructive species. It should be 

 added that the only forms considered by any one as identical Avith P. rapae are those 

 described by myself as P. marginalis and by Mr. Reakirt as P. yreha. They came 

 from California, Oregon and AVashington Tei-ritory. 



' "With regard to the nature of the documentai-y evidence a few words may be said. 

 One would expect that much might be leai-ned from agricultural and horticultural jour- 

 nals about the movements of the butterfly, but a great amount of time has here been 

 wasted in vain seai-ch; very little Avas to be found and that little generally so vaguely 

 stated as to be valueless. Direct enquiry has been ahnost the sole resource of value after 

 the entomological journals, and especially the pages of the Canadian Entomologist. 



In the mass of information received from veiy various quarters in reply to my circular 

 of inquiry, it has of course been impossible to Aveigh the evidence for exactly Avhat it Avas 

 Avorth. Some of it, as Avas to be expected, had to be throAvn out altogether as coming 

 from those Avho Avere not sufficiently observant to have distinguished betAveen the ncAV 

 pest and its allies, also destructive to cabbages. To adopt indiscriminately all the data 

 oflfered Avould lead to a chaotic result: Ave should be obliged for instance to say that the 

 butterfly appeared in Ohio in 18G5, Avhen it had only that year crossed the northern bor- 

 der of ]S"eAV England; or that it reached central Illinois in 1871 or 1872, or even in 

 1859 Avhen it had not yet been borne across the ocean; or that it appeared in Georgia 

 in 1862 and Avas abundant there in 186(), some ten years before its time. More possibly 

 correct is the nearly accordant testimony of no less than three repoi'ters, whose judgment 

 I haA'e no means of testing; they agree in giving 1861 or 1865 as the date of the first 

 appearance of the l)utterfly in eastern Pennsylvania and a fourth refers to it hesitatingh', 

 perhaps as a matter of report; it is possible that it might have been brought across the 

 ocean direct to Philadelphia at that date, but as it did not attract the attention of other 

 entomologists in and about Philadelphia or make its impression on the country around, 

 the suppositioai is rendered highly improbable; nor do the facts given above regai-ding its 

 spread about New York lead us to admit that it reached that city from Philadelphia. 

 It is far easier to suppose either that a mistake was made by each observer in the spe- 

 cies concerned, or that the memory was at fault, — all these statements coming to me in 

 ansAvcr to my enquiries last autumn ; none of them are j^rinted records. The point may 

 perhaps be best solved l)y entomologists of that region, if they Avish to folloAV it up; in 

 which case the details in my possession Avill l)e furnished to any competent person. 



I have not mentioned above a I'cport made to me by an entomologist, Mr. George 

 Bowles, Avhose specialty is Coleoptera, Avho states that Avhen on a natural history expe- 



