734 THE BUTTERFLIES OF NEW ENGLAND. 



Occurrence in New England. Archippus occurs throughout New 

 England, but is much more rare in tlie northern than in the southern part ; 

 though even in the hitter it can hardly be called abundant, for usually 

 specimens must be captured singly. Yet now and again it swarms, as in 

 the autumn of 1871. In some localities it is especially numerous ; such 

 places, for instance, as islands oiF the coast, or broad, sandy sea beaches, 

 where no Asclepias grows. Is it that an innate propensity for geograph- 

 ical extension leads this butterfly to the last possible limit? Mr. Thaxter 

 once found it in great numbers on Appledore, the largest of the Isles of 

 Shoals, N. H., which has a surface of about five hundred acres ; yet there 

 was then no trace of milk weed upon any of those islands, which he has 

 explored thoroughly. Again, on Fire Island beach, Long Island, during 

 the last of August, 1870, Prof. S. I. Smith found this butterfly in thou- 

 sands wherever flowers occurred, while they were uncommon on Long 

 Island itself. He counted eighty on a single small plant of Erechthites, 

 and yet looked in vain for Asclepias. See also on a succeeding page Dr. 

 Hamilton's account of their abundance at Brigantine Beach, N. J., equally 

 barren of Asclepias . 



Haunts and swarms. The butterflies occur in open ground, in 

 meadows and pastures and not infrequently in gardens. Mr. Wallace 

 gives a similar account of their haunts in the Amazons valley, describing 

 them as "open grounds, dry and barren places" ; but when the butterflies 

 congregate, as seen above, they seek the branches of trees. "In the 

 evening and in cloudy weather they arc found resting on the stems of her- 

 baceous plants ; they never are to be found in the thick part of the woods, 

 but are common in the open spaces of the forests, and prefer meadows and 

 plantations ; . . . [they are] abundant even in the largest towns of the 

 middle and northern states (Doubleday, Gen. diurn. Lep., i: 90). 



The species of this group are known all over the world for their rich- 

 ness in individuals, and ours is no exception to the rule ; the large size of 

 the insects makes the fact the more conspicuous. In the western prairies 

 they may be found in myriads. 



Thus Mr. J. A. Allen (Trans. Chic. acad. sc, i: 331) writing from 

 Iowa says : — 



This extremely abundant butterfly seems to prefer the open prairie, but is driven to 

 the groves by the winds which sAveep furiously over the prairies in the summer mouths, 

 and especially in September; here the butterflies are collected in such vast numbers on 

 the lee sides of trees, and particularly on the lower branches, as almost to hide the 

 foliage, and give to the trees their own peculiar color. This was not seen in one 

 grove alone, but in all of those which were visited about the middle of September. 

 If unmolested, they remained quietly on the trees; if disturbed by blows npon the 

 trunk or branches of the tree, they would rise like a flock of birds, but immediately 

 settle again, either on a contiguous tree or upon higher branches of the same. At 

 New Jefferson, a little later in the year, Avhen the gales had abated, thev Avere seen 



