SWARMING OF ARCHIPPUS.
Dear Sir,—
I was surprised to learn from the letter of Mr. Edwards in your last issue, that the flocking of archippus is not a well known fact in Entomology, and in view of this I venture to add a few facts in regard to it which may be of interest.
Fig. 6.
While spending the winter of 1875-76 in Apalachicola, Florida, I found one of these archippus swarms in a pine grove not far from the town. The trees were literally festooned with butterflies within an area of about an acre, and they were clustered so thickly that the trees seemed to be covered with dead leaves; fig. 6 will enable the reader to form some idea of their appearance thus grouped. Upon shaking some of the trees a cloud of butterflies flew off, and the flapping of their wings was distinctly audible. They hung in rows (often double) on the lower dead branches, and in bunches on the needles. I find by my note book that visiting the flock towards evening, it was receiving additions every moment. I caught a net full off a bunch of dead needles, and, walking away to some distance and letting them go, all but three returned to the flock. The question as to where they came from seems a very interesting one. I was told by Dr. A. W. Chapman that there was hardly Milkweed enough in all Florida to produce one of these flocks, which doubtless do not confine themselves to Apalachicola. During my visit I found two more flocks not far from the first, but neither of these was as large. I should mention that I often observed examples among them in coitu.
I have seen archippus flocking at the Isles of Shoals, N. H., towards evening, in very much the same manner, having flown nine miles from the mainland. I have also seen clusters of Vanessa J-album on tree trunks at dusk in New Hampshire, which seemed to present a parallel to the archippus flocks, though of course on a very small scale.
R. Thaxter, Newtonville, Mass.
Dear Sir,—
Last summer I discovered, unfortunately too late, that a large Cossus was working in some large and very old Oak trees near here. I hope next June or July to find out what it is, as I shall construct nets to envelop the tree trunks of several of these so infected Oaks. None of my correspondents have been able to give me light on the subject; they think it possible that this is a new species, and urge close observation, advice which I hope to be able to follow.
I also purchased five large trees of a coarse variety of Poplar, known here as Cottonwood, that were to be cut down, as they had commenced dying, “caused by a grub working in them.” I found it to be a Cossus larva, but not as large as that working in the Oaks. Judging from a comparison of the empty pupæ cases found in them, which in these Poplars were very numerous, it is not the one described by Mr. Bailey in last January number as “Cossus centerensis” but seems more like Xystus robiniæ. I had three of the trees cut down in order to obtain the pupæ; judge of my surprise and disappointment when my man came in, telling me he could find none but “lots of nasty grubs, of which he had given the near chickens probably a hundred or more,” not thinking them valuable to me. I sent him back with instructions to preserve every larva he could find, and I now have about fifty in every stage of development from the half-inch beet red, the nearly two-inch long pink, to the about two and a half-inch long greenish-white larva. I have some in the wood in their own burrows, and have put the rest in sawdust; and I have ordered him to cut me pieces of that wood, bore some holes in the ends and put in the other larvæ, and cork it in, leaving a few air-holes; with these I hope to complete my observations in a warm room. I did not know before that these hybernated in the larval state, much less did I think they would be found of different moults.
A. H. Mundt, Fairbury, Ills.