1878 



OF PIERIS RAPAE IN NORTH AMERICA. 63 



remaining' data are for Illinois and Michigan; the butterfly had covered the lower half 

 of the lower peninsula of Michigan (A. J. Cook, E. W. Allis) and part of Illinois. The 

 specific points which it had reached in the latter state are the region about Chicago, 

 — Maplcwood (C. Thomas, G. 11. French), DeKalb Co., sixty miles west of Chicago (P. 

 M. Webster), — Decatur (W. Barnes), and Champaign, in the autumn (C. Woodwortii). 

 The first two of these may easily have been the mere extension of the Chicago colony, 

 the latter two of the Indiana, but, in all probability, the succeeding year saw a blending 

 of all the colonies both north and south. 



For then, 1878, not only is almost the whole of Illinois invaded, but the advance guard 

 has pushed across the Mississippi and intrenched itself in Iowa and Missouri. According 

 to Dr. C. Thomas, it appeared at Carbondale early in tlie yeai' and " in injurious 

 numbers" at Springfield (9th Rep. Inj. Ins. 111., 9). It had crossed the Mississippi 

 at at least two points. Prof. R. R. Rowley writes me from Cun-yville, Pike Co., Mo., 

 that he collected two specimens on radish ])lossoms at Louisiana in that county in July, 

 1878, and Prof. S. M. Tracy says that he noticed it at Columbia, in 1877, the first year 

 of his residence there^ Fuilhei', Mr. J. M. Myers writes me that five or six specimens 

 were taken at Fort Madison, Iowa, in the autumn of 1878; and the same fact is reported 

 by Mr. A. W. Hoflmeister (Trans. Iowa Hort. Society, 1879). There can therefore be 

 little doubt that it was in this year that it first crossed the Mississippi. In Tennessee too, 

 it was close to the Mississippi in 1878, for according to Mr. F. P. Ilynds it appeared this 

 year at Ralston Station in Weakley Co.; and it was in March recorded from Asheville, 

 N. C, by Mr. W. Y. Andrews (Can. Ent., x, 98). 



In 1879 it had extended up the peninsula of Michigan, having been taken at Luding- 

 ton either this year or the preceding by Mr. jST. B. Pierce, and had invaded Wisconsin, 

 appearing in May about Racine (P. R. Hoy) and being abundant thei-e (O. S. 

 Westcott) although it did not reach Milwaukee that year (R. T. Chui-ch). Dr. 

 Hoy's printed statement will be found in his list of Wisconsin Lepidoptera, and should 

 be noticed by any one led astray by the statement in the American Entomologist (ir, 

 79) that it was said by Dr. Hoy to be tolerably common in Wisconsin in 18G9. This 

 last jjublication may account for the statement by Dr. Fitch in his thirteenth Rejiort on 

 New Yoi-k insects, in speaking of the new cabbage pests, that " the present year (1870), 

 probably favt)red ]:»y the protracted drought, they have suddenly overspread a large por- 

 tion of the middle and western states," when in fact they had not extended westward 

 beyond the middle of his own state. Possibly it was based on the statement already re- 

 ferred to in Edwards' Buttei-flies. Mr. Riley has also stated (U. S. Agric. Rep., 1883, 109) 

 that it had appeared in Green Bay (Wisconsin) in 1874, but that probably his correspond- 

 ent mistook an allied species for it. In Iowa it made rapid advances. We have already 

 seen it at Fort Madison in the southeastern corner. It probably appeared in 1878 also 

 at Keota in Keokuk Co., for it was destructive there before the end of 1879 (A. S. Van 

 Winkle). At Muscatine, according to Miss Alice Walton, now Mrs. Beatty, it appeared 

 in the latter part of May (Proc. Mnsc. Acad., Nov. 3, 1879) and according to Mr. F. M. 

 Witter (Proc. Iowa Acad., 1875-80,21-22) became destructive that year. It appeared 

 this year also in Linn Co., where it was very destructive (Riley). But it went beyond 



' Tliis is cei'tahily possible, but it was more probaljly in 1878, to judjje by other repoits. 



