1080 THE HUTTKUFLIES OF NEW ENGLAND. 



In the early days of June and particularly about the 7th, the huttei-flies 

 appeared all over the central portions of Europe moving, as a general rule, 

 at right angles to or against the wind, but \vith a prevailing direction from 

 the south-west toward the north-east. They passed over all obstacles with- 

 out hesitation ; thus on the 5th of June thousands of them were found 

 dead on the snow around the St. Gothard hospice, only a day or two after 

 which they appeared in immense swarms to the north of the Alps. That 

 it was not simply a superabundance of butterflies already existing in the 

 region, but an inflow from outside, seems to be abundantly proved by two 

 facts : first that in the principal regions of the invasion, cardui does not 

 appear upon the wing (excepting in the few which hibernate) until the 

 middle or end of July, whereas the invasion took place at the end of May 

 and the first half of June ; and second by the condition of the specimens 

 concerned in the invasion ; wherever captured, with a single exception, that 

 of Ritter, all specimens were noted as very worn and faded, indicating that 

 they had flown from an immense distance. Oberthiir, capturing speci- 

 mens of the flight which made its appearance at Rennes on the 10th of 

 June, remarked that they belonged to a very characteristic African type, 

 noticeable for the fact that the brighter parts of the upper wings are very 

 much paler and less I'osy than in the type found in France. Specimens, 

 indeed, seemed to him to be preciselj^ like those which he had in his col- 

 lection coming from Abyssinia. Now as it is well known that cardui flies 

 during the entire winter in the north of Africa, laying its eggs and 

 raising its broods throughout this season in Egypt, where I have my- 

 self seen it in the imago, caterpillar and chrysalis state in the greatest 

 profusion during the month of March, there is no reason for disbe- 

 lieving the conclusion that nearly all who have examined the question 

 appear to have reached and which has been formulated by several writers, 

 that this was literally an in^^asion of butterflies which had flown across the 

 Mediterranean and spread over the greater part of Europe. It does not 

 seem to me necessary to suppose they crossed at any given point or during 

 the day-time only. 



According to Speyer, the movement of the butterfly streams were ob- 

 served as far as the 50th degree of latitude, but accompanied, he says, by 

 an unusual frequency of this butterfly otherwise over all England, Ger- 

 many, Hungaiy and even as far as Finland. Schmidt, however, without 

 apparently having observed any flight, states that at Vismar, as far north 

 as the Baltic coast and near latitude 54°, cai'dui was excessively abun- 

 dant, and all very woi'n and faded ; and it is quite possible that the 

 superabundance of the butterfly found to the north, in England and else- 

 where, during this year may have been due to the presence of the invad- 

 ing horde whose progeny they represented. 



To follow for a week the fortunes of tliis invading horde, we would observe 



