152 



Pieris rapae in Mid-ocean. 



Dr. J. L. LeConte recently sent me a butterfly taken last 

 August, by Dr. R. H. Lamborn, on the steamship Abyssinia, 

 eleven hundred miles east of New York, while on her passage 

 from Liverpool. When first seen, Dr. Lamborn writes, the 

 insect was " flying among the rigging and following the ship, 

 which was moving over a calm sea at the rate of about twelve 

 miles an hour. The wind had been steadily south-west during 

 the passage." This butterfly is a female of Pieris rapae, and is 

 in perfect condition, excepting that it was rubbed in capture. 



This throws light, if any were needed, on the manner of the 

 introduction of this pest into America. Undoubtedly the but- 

 terfly had not flown from land, but the caterpillar from which it 

 sprang had been introduced into the vessel in the cabbages in- 

 tended as food while in port or during the voyage ; and in this 

 particular instance the butterfly had emerged from the chrysalis 

 (which had suspended itself in some safe nook on board) previ- 

 ous to the completion of the voyage. This must now be a weekly 

 occurrence in midsummer, and it would seem as if no amount 

 of precaution, likely to be taken, would have kept Pieris rapae 

 out of America many years longer. I have evidence that the 

 insect was independently introduced into the port of New York, 

 and swarmed in the vicinity of that city, before the Canadian 



hordes had reached Albany, on their southward march. 



Samuel H. Scudder. 



Hibernation of Amphipyra pyramidoides. In Chicago, Illinois, 

 this insect is single-brooded, tor a poplar-feeding larva found the latter 

 part of May, and which spun upon the 14th of June, did not produce the 

 moth till the following April ; but specimens obtained near St. Louis often 

 produce the moth during July of the same year that they are found as 

 worms. In this last case a second brood is doubtless produced the same 

 year, though it is barely possible that the moths winter over and do not 

 deposit till spring ; for they are characterized by having very flat bodies, 

 and with their wings folded flatly on their backs they are often found hid- 

 ing in narrow cracks and crevices where they seem to love to shelter. — 3rd 

 Mo. Ent. Rep., p. 73. 



The above, written in 1870, shows conclusively that this insect sometimes 

 passes the winter in the chrysalis state. My experience, since, agrees with 

 Mr. Roland Thaxter's, and I have no doubt that the species frequently 

 hibernates also as a moth. There is much greater irregularity in the devel- 

 opment, time of appearance, and hibernation of insects than most entomol- 

 ogists incline to allow. C. V. Riley. 



No. 22 was issued March 6, 1876. 



