show that I am not the only one who has noticed an abundance of Hymenoptera in Colorado, I would call your attention to the papers of Mr. E. T. Cressen in the "Proceedings of the Entomological Society of Philadelphia," and particularly to a "Catalogue of Hymenoptera from Colorado Territory," published in vol. iv. of those "Proceedings."
Lepidoptera.—In the list referred to I have enumerated forty-seven species of butterflies, which I collected, with but one exception, in the mountains. I have never anywhere seen butterflies so abundant as they were in the valley of Clear Creek, between Golden City and Idaho Springs, on July 1, 1872. The air seemed literally to swarm with them. I cannot imagine how the entomologists of Mr. Meehan's party found them so scarce. Wherever there were flowers, I was sure to find butterflies, though, of course, they showed a preference to some kinds. Of the Heterocera I brought home over sixty species, mostly undetermined; but this is no indication of the actual number occurring, for I took no pains to hunt them, and only preserved what came to me.
The common morning lined sphinx (Deilephila lineata) was frequently seen at dusk, hovering about various flowers, being especially fond of the yellow thistles. I do not now recall any peculiarity regarding the other species, except that they were quite plenty. Perhaps 1872 was an unusually favorable season; but Mr. Theodore L. Mead writes that in 1871 he spent four months in Colorado, mostly in the South Park region, where he collected over 100 species and 3,000 specimens of butterflies, and 4,000 specimens of beetles, etc. I believe Mr. Mead has published an account of his observations on Colorado butterflies in the zoölogical report of Lieutenant Wheeler's explorations west of the 100th meridian. I would also refer you to an article on Coloradian butterflies, by Tryon Reakirt, in the "Proceedings of the Entomological Society of Philadelphia," vol. vi., 1866, and to the more recent works of W. H. Edwards, and others.
Although Mr. Meehan does not mention them, I have an idea that the Coleoptera and Hemiptera are often quite active agents in the fertilization of plants. Certainly the number of species of these orders found in flowers was very great, and it is more than likely that in 'going from flower to flower they carry some of the pollen with them. The Meloidæ, Chrysomelidæ, Cerambycidæ, Cleridæ, Malachidæ, Mordellidæ, etc., were especially noticeable by the large number of species and individuals. Trichodes ornatus (Say) was exceedingly abundant in the flowers of Potentilla fissa, and, after that had generally gone out of flower, on the flowers of the white and red geraniums and other plants. Owing to the fact that at the time I made these collections I knew the names of neither the plants nor insects, I cannot now remark more definitely on their habits. A full list of the species collected will be found in the "Proceedings of the Davenport Academy," vol. i.
I think what I have said shows that there is no unusual scarcity of insects in the Rocky Mountains of Colorado, at least wherever there are flowers. It should not be overlooked, however, that within the Rocky Mountain regions there are arid districts where neither insects nor flowers are particularly abundant; and also that a similar state of affairs exists in a dense pine or spruce forest. Wherever flowers are plenty in the Rocky Mountains, so are insects always; but the reverse is often not true, for I have frequently known certain insects to be exceedingly plentiful where there were no flowers. The "entomologista" of Mr. Meehan's party were certainly very unfortunate in finding so few insects. I believe Mr. Morrison, of Cambridge, an excellent collector, intends spending next summer collecting the insects of Colorado, and he will be able to add his testimony to the case.
Mr. Meehan has certainly read Lieutenant Carpenter's paper in Hayden's Report for 1873 very carelessly, or he would have seen that the five species of butterflies he speaks of as being the "doings of a whole season" were all Alpine, and collected above the timber-line, a region which a little further on he rules out of the discussion. It is certainly true that these Alpine "Lepidoptera are undoubtedly peculiar to high latitudes and great elevations;" but