EUPLOEINAE: ANOSIA PLEXIPPUS. 741 



Montreal in May. In tlie extreme soutliern portions of New England 

 and the neighboring districts, we have not infrequent appearances of hiber- 

 nating butterflies early in May. But neither hibernators nor their progeny 

 in the preparatory stages, — the only absolutely certain proof of an early 

 brood, — are, with possibly rare exceptions, to be fnnid in the northern half 

 or more of New England, either in May or early in June. The first oc- 

 currence of the insect there in any form is much later in the season, gen- 

 erally by the middle of June, occasionally by the very first, sometimes 

 not until the very end of this month, when fine fresh butterflies make their 

 appearance, at about the same time as, or a trifle later than the advent a 

 little further south of the first fresh brood of butterflies from ejjas of the 



CO 



same season, thus giving all the appearance throughout New England of 

 an identical swarm of butterflies, varying in time from those found next 

 the southern borders of New England only so much as would be exi)ected 

 from latitude. 



This brood is in my opinion to be accounted for only on the supposition 

 that they are colonists from the south, which have flown to more north- 

 ern districts from that impulse to wander which is one of the psychologi- 

 cal characteristics of this buttei-fly. This hypothesis is further supported 

 by the essentially tropical nature of the butterfly, Avhich would prevent 

 its establishing itself as a permanent resident rather than as an annual 

 visitor of northern districts ; by its well-known vast power of flight, of 

 which illustrations have been given ; as well as by its comparative history 

 in the south and by the known autumn migrations of the butterfly in the 

 opposite direction, of which we have given proof. These butterflies begin 

 in New England to lay their eggs usually in the first week in July, 

 but occasionally as early as the middle of June. Dr. Harris records some 

 caterpillars found on the 28th of June which had reached the length of an 

 inch on the 5th of July, and I have found them in Shirley, Mass., of the 

 length of six millimetres, therefore probably in the second stage, on the 22d 

 of June. These were unusually early caterpillars of the brood which had 

 flown from the south and which sometimes makes its advent early in June. 

 Both Mr. F. H. Sprague and myself have found them about Boston as 

 early as the 2d of this month in good condition, and single additional 

 specimens were found in the same year by Mr. Sprague on the 9th and 

 15th of June.* They never, however, become at all abundant before the 

 first week in July, when the eggs are ordinarily laid. The eggs continue 



* Since this account of the life history was passed the winter unscathed, as I think never 



first published (Psj-che, v : 63) Mr. Sprague happens, from all accounts. The season was 



observed a single butterfly on May 30 in a backward this year. May 25 I saw the first 



"perfectly fresh condition"; and as during young plants in a patch of Asdepias in a sunny 



the same season (1888) no Asclepias was o?f J o/ spot on a lawn whiili I had examined every 



the ground in the vicinity of Boston before two days for a fortnight, and a comparison 



May 20th, it is evident that either it had flown with other spots makes me confident of the 



from the south, as I believe, or that it statement above. 



