Letter to Edward Newman October 1832

by Alexander Henry Haliday

Sir,—I send you a list of some Diptera occurring about Holywood, in the county of Down. Should you think it not unsuited to the pages of the Entomological Magazine, the Notes appended will afford the necessary explanations of the nomenclature adopted, where it differs from that of Meigen or of the published British Catalogues. As I am aware that a bare local catalogue may not seem of sufficient general interest to occupy so many pages, I should probably not have thought of it had time allowed me to offer any contribution of greater labour and detail. Perhaps, however, as referring to a district in this respect nearly unexplored, this list may afford some hints for the advancement of our Insect Geography. I am sorry therefore to present it in so meagre a form, many of the most extensive genera being unexamined in detail. These are indicated by the asterisk prefixed ; and some of them I have thought it better to pass over entirely. Perhaps, however,a few facts may be gleaned from it, such as it is. The total absence of the families of Bombylii and Asili is observable and, considered in connexion with the small proportion which the British species bear to the European in the aggregate, seems a result partially determining the law of progressive distribution among these forms. The disappearance or extreme rarity of the finer genera (the Optimates) among the Tabani,Stratiomydes, Syrphi, &c. may also be remarked, as well as the absence of various conspicuous (and in this point of view more insulated) groups, such as Ctenophora, Aspistes, Pachygaster,Platypeza, Diaphorus, Echinomyia. Gymnosoma, Micropeza, Platystoma, &c. On the other hand, the predominance of particular tribes may afford some indications ;the Dolichopi, as a family, are pretty full (so also the minuter Tipulidae, though not appearing from this catalogue); the Muscidae, of less typical structure (all the genera after Coenosia,or perhaps Scatophaga) are by no means scanty. A few groups seem to approach their culminant point ; Coelopa, a genus unknown to the shores of the continent, and even on the Scanic peninsula confined to one described species, here numbers five or six, all rich in individuals, and exercising no unimportant functions in the economy of nature. Tachypeza arenaria, which sometimes swarms upon our coasts, has many analogies of structure with its companions, the swift-footed but heavy-winged Oryymae and Coelopae, and like them is probably confined to a northern range. Not to detain you further with remarks that may appear obvious or trivial, I will only add my best wishes for the success of your undertaking ; and am, Your very obedient, &c. Alex. Henry Haliday. Clifden, near Holywood, Oct. 1832.