Published online by Cambridge University Press: 10 July 2009
The only Dipterous parasites of tsetse-flies at present known belong to the family Bombyliidae, and to the genus Thyridanthrax, O. Sack., as enlarged by the late Professor Bezzi. Hitherto the species of this genus definitely stated in literature to be parasitic in the larval stage in Glossina pupae consisted solely of Th. (Villa) lloydi, Austen, and Th. (Anthrax) abruptus, Lw. In the following pages the number of species of which specimens have been bred from pupae of tsetse-flies is raised to seven, including three species which are described below for the first time. With one exception (Th. argentifrons, sp. n.), in which the holotype emerged from a pupa of Glossina tachinoides, Westw., while a paratype was bred from a pupa of G. morsitans, Westw., form submorsitans, Newst., these flies are not known to attack any species of Glossina other than G. morsitans. Whether it will ever prove possible to make practical use of parasites for the purpose of tsetse-fly control, is a question for the future. In this connection, however, it is perhaps of interest to note that, whereas six out of the seven species dealt with below occur either in Rhodesia, or in countries to the south-east or north-east of that territory, the seventh species (Th. argentifrons) has been met with in Northern Nigeria.
* In the present paper, following the example of the late Prof. Bezzi, Thyridanthrax, as expanded by this author (cf. Bezzi, Transactions of the Entomological Society of London for the Year 1911, p. 625, 1912 ; and “ The Bombyliidae of the Ethiopian Region,” p. 192, 1924), is treated as a distinct genus, rather than, as by S. J. Paramonow (“ Zur Kenntnis der Gattung Hemipenthes Lw.” ; Encylopédie Entomologique, II, Diptera, T. III, Fasc. 4, p. 150, 1927), as a subgenus of Hemipenthes, Lw.Google Scholar
* For names and illustrations of colours used for descriptive purposes in the present paper, see Ridgway, “ Color Standards and Color Nomenclature ” (Washington, D.C. Published by the Author, 1912)Google Scholar.
* The head of this specimen, while under examination, was unfortunately lost.
* Cf. Austen, Bull. Ent. Res., v, pt. 1, p. 91, footnote, 04 1914Google Scholar ; and Lloyd, ibid., vii, pt. 1, p. 76, fig. 2c, May 1916.
* The record “ N. Nigeria ” for this species (Marshall, Bull. Ent. Res., vi, pt. 3, p. 256, note*, December 1915 ; and Bezzi, loc. cit., 1924) rests on an error in identification ; the ♀ specimen referred to by Dr. Marshall (N. Nigeria : Minna, 18.x.1910. Dr. J. J. Simpson) presents such differences in wing-marking as, in the writer's opinion, to prevent it from belonging to Th. abruptus, Lw.
* For the opportunity of examining the type of this species the writer is indebted to the courtesy of Prof. Yngve Sjöstedt, of Riksmuseet, Stockholm, who most obligingly forwarded the specimen to London for study.
* Owing to the condition of the available material, it is impossible to describe Th. beneficus quite as fully as could be wished ; it is hoped, however, that the details given above, in conjunction with the figures, will be sufficient to place the identity of the species beyond doubt.