OF PIERIS RAPAE IN NORTH AMERICA. 61 



who, in a recent letter to me, after mentioning the year 1870 as one wliich was remarka- 

 ble for the number of Lepidoptera seen in that city, says that P. i-apae (of which he 

 possessed English examples in his cabinet) was not to be found, but " in 1873 I observed 

 it as not uncommon in this city, and recognized it at once, while flying, as distinct from 

 its congeners P. monuste and P. ijrotodice ... I have seen it T think eveiy year since." 

 This appears to be an unquestionable independent introduction of the species from a 

 coasting vessel, and it is due to this probably that we find it invading the southern At- 

 lantic states sooner than we should otherwise anticipate. In the curves, therefore, I have 

 given this new southern horde a distinct claim to local independence, and brought the 

 northern curve to the ocean at a comparatively high latitude. 



In 1874 we again hear of the insect to the east of its point of origin, K. Corneau report- 

 ing it as rare at Godljout i-iver on the lower St. Lawrence, the northeasternmost point 

 from which it has yet been recorded (Can. Ent. vir, 208) ; its progress westward ,„„- 

 in Canada seems to have been very slow. It was abundant now at Hamilton but it 

 did not reach Paris this year or certainly not until the vei-y end of the year. It had be- 

 come noticeable at Cleveland by its ravages during this summer^ as well as in western 

 Pennsylvania (T. B. Comstock, Am. Kat. ix, 426). It made its appearance among the 

 mountain valleys of West Virginia in September, where it became abundant the fol- 

 lowing spring (W. H. Edwards, Pap. i, 96). It was "by no means rare" in Virginia 

 (Bethnne, loc. midt.) 



Of the extension of the southern horde we know nothing, but from the record of later 

 dates I have assumed an enlarged curve wliich seems best to agree with the facts. 



But here enters a new factor. Dr. A. W. Chapman, a well-known and experienced 

 lepidojiterist, in response to my circular, writes to me from Apalachicola, Florida, that the 

 butterfly first appeared there in 1873 or 1874; adding that it has not yet become com- 

 mon, only half a dozen being seen in a season. Here we have a second southern coastal 

 introduction, unless indeed it was imported from Charleston by rail direct, as seems more 

 probable. Its appearance, however it came about, at these two southern stations at such 

 an early period explains why, when the insect does not flourish so well in the extreme 

 south as fiirther north,^ it managed to reach Alabama at least as soon as it obtained a foot- 

 hold beyond the Mississippi. 



Turning now to the year 1875 and beginning as before at the north, we find that ac- 

 cording to Mr. Saunders it reached Paris, Ont., in the spring of 1875, and London in 

 August (Report Ent. Soc. Ont. 1875, 31; Can. Ent. vir, 163). The same good 

 authority tells us {ibid.) that it had reached western Ohin, and a gardener in 

 southwestern Ohio reports that it first troubled him in 1876 at Mt. Repose, Clermont 

 Co., and therefore presumably reached that place by 1875 (F. G. Fisher) . It did not how- 

 ever reach Cincinnati until the following year (C. Dury) though it had followed the 

 western Alleghanies down to Maryville, Blount Co., eastern Tennessee, a little south of 

 Ivnoxville, where Mr. E. M. Aaron saw it in 1875. It was now common in West Vir- 

 ginia, and presumably extended into North Carolina, though we have no report from 



' Dr. J. F. Isom reported tliat it first appeared at Cleve- " In evidence of tliis, the fact that it is still scarce at 



land In the spring of 1S75 (Can. Ent. vu, ISO) ; but he is Apalachicola is supported by its failure to invade the pen- 



certainly in error. insula of Florida. 



MEMOIRS BOSTON SOC. NAT. HIST., VOL. IV. 9 



