a Second Supplement to his 'Historical Review of the genus Acentropus;' and the author, writing in June, 1875, prefaces it with the welcome announcement that he has worked up the literature to the present time, 'as in all prohability I shall be able in this summer to complete the history of the mode of life and the different stages of A. niveus.'
"Whether this expectation has been fulfilled, either in 1875 or 1876, I do not know. But, however this may be, I am sure Heer Ritsema will be glad to learn that, though he and I failed to convince Newman that the genus is properly placed in the Lepidoptera, we did make a convert of Doubleday. In a Supplement to his 'Synonymic List of British Lepidoptera,' published in 1873, Doubleday for the first time admitted Acentropus into that order. Its precise place in the order is not indicated, but it is immediately followed in the Supplement by a species of Ebulea (Botydæ), which sufficiently shows that the position which Doubleday would assign to Acentropus is in or near the Hydrocampidæ.
"It may possibly be remembered that, in a paper which the Society did me the honour to publish in the 'Transactions' for 1872 (pp. 121 and 281), I adduced some arguments tending to show that there is really one species, and one only, of this genus; and in a note on p. 156, the position is thus summed up;—'I am quite in accord with Ritsema when he says that A. Hansoni, Garnonsii, Nevæ, badensis and germanicus are not specifically distinct from A. niveus; but I go a step further, and say that A. latipennis is identical with A. Hansoni.' Ritsema is now satisfied that A. latipennis is identical with A. Hansoni, but still thinks that there are two species, of "which one (A. niveus, Oliv. = A. Garnonsii, Curt.) has a female with rudimentary wings, and the other (A. latipennis, Möschl. = Zancle Hansoni, Ste.) has a female with normally developed wings. Doubleday, in the Supplementary Catalogue already mentioned, does not go into the synonymy at length, but records one species only, under the name of A. niveus, giving latipennis as a variety, thus:—
Acentropus niveus.Niveus, Olivier?
latipennis, Möschl., var.
"I am not able to throw any further light on the specific identity or distinctness of the two forms. Ritsema, however, refers to his having found many specimens, all males, at Arnheim, and to the capture at Huissen (near Arnheim) of a winged female, which he recognises as A. latipennis. 'By this capture' (says he, at p. 15), 'I am fortified afresh in the opinion that there are two species.... For it would be otherwise inexplicable that amongst the innumerable winged individuals captured by me at Overween, not a single female occurred, and that I, by breeding from larvæ coming from the same place, obtained only females (in number already amounting
