Page:The Zoologist, 1st series, vol 1 (1843).djvu/204

176 height on that day, and was not disappointed. About 11, A.M., they emerge from the chrysalis, and ascend the trunks of the oaks; and from that time until half-past 4, P.M., T captured forty-five males and eight females, notwithstanding that it rained incessantly all the time, accompanied with high wind, or I could have taken many more: among them were some beautiful varieties. It is a great peculiarity about this insect, its simultaneous appearance; so that unless the collector is at the locality on that day, his success is very doubtful afterwards, as hut few stragglers are seen; what becomes of them I cannot tell. On the same day, with similar weather, a friend of mine was capturing Nyssia zonaria, so very local to Liverpool. This insect appeared in great abundance; to use his own words, " he could have captured five hundred specimens if he had wanted them." They leave the chrysalis at the same hour as the preceding species, but last much longer. Biston prodromarius, found also in Dunham park, was at its height on the 5th of April, leaving the chrysalis from 2, P.M., till 6. Although the park was well searched for some days afterwards, not a dozen specimens were taken, and those chiefly between the hours mentioned; thus proving the necessity of being acquainted with their hours of appearance if we intend to be successful in their capture. Larentia multistrigaria, Achatia piniperda, Anisopteryx leucophearia, and the true female, a very different insect to the female of Anis. stictaria, so frequently placed in cabinets for it;—these, and some beautiful varieties of Diurnea fagella, quite black, are the only insects worth recording that I have captured in this neighbourhood so far this season.—Id.

Note on the periodical occurrence of Colias Electra, Linn. [C. Edusa, Steph.] I see in the last 'Zoologist,' (Zool. 113) that the Rev. W. T. Bree has expressed surprise that the remarkably fine weather which we had last year (1842) did not produce Colias Electra as well as its congener, C. Hyale. Now, C. Hyale has been conjectured to appear every seven years, (Entomol. 388); and from the experience that I have had in catching C. Electra, which, in some seasons is a common insect on the cliffs in this neighbourhood, it seems to recur plentifully every fourth year, though scattered specimens may sometimes be caught in the intervening time. If this be the case, they will be found this year (1843), as they were very common in 1839. It is not, however, the experience of a single person from a single place that can settle such a point, but I was glad to see (Entomol. 385) that you mention their being found at the late Croydon canal in 1835, and again, Mr. Bree stating it to have occurred at Dover in 1831, Both these dates agreeing with mine, seem to show that when it appears in one part of the kingdom it appears in all: and I certainly think that if proper data were procured, the recurrence of several insects, whose appearance is now supposed to be irregular, might be predicted almost with certainty, as in the case of the Cicada septemdecim of the United States.—Robert C.R. Jordan; Teignmouth, April 18, 1843.

Note on the periodical occurrence of Colias Electra. My own memoranda tend to corroborate Mr. Jordan's views as to the appearance of Colias Electra in some abundance every fourth year, and particularly in 1831, 35, and 39, in which years it appeared simultaneously in many of the southern counties. This quadrennial appearance occurs in some degree with other insects, for instance, the common cockchafer and the goat moth; but in both these instances the insect is supposed to be four years in arriving at maturity, which can scarcely be the case with a butterfly. The occasional appearance of insects during the intervening years, does not militate against the quadrennial theory.—Edward Newman.

Note on the remarkable abundance of hybernating Butterflies. On Sunday last,