Illustrations of African blood-sucking flies other than mosquitoes and tsetse-flies / by Ernest Edward Austen.

  • Ernest Edward Austen
Date:
1909
Catalogue details

Licence: Public Domain Mark

Credit: Illustrations of African blood-sucking flies other than mosquitoes and tsetse-flies / by Ernest Edward Austen. Source: Wellcome Collection.

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    The only species of Lyperosia of which the Life-history, biology has yet been studied is the one just mentioned, the life-history of which has been investigated in America by Riley and Howard.* According to these authors, L. irritans oviposits on freshly dropped cow-dung ; the eggs, which are “ laid singly, and never in clusters, and usually on their sides on the surface of the wet dung ; seldom inserted in cracks,” are light reddish brown in colour, irregularly oval in shape, flattened on one side, and from 1.25 to 1.37 mm. in length, by 0.34 to 0.41 mm. in width. The newly-hatched larvce, which are pure white, descend into the dung ; when full-grown the larvae are dirty white in colour and 7 mm. in length. The posterior stigmatic plates, situate on the hinder surface of the terminal or anal segment, are large, very dark brown, nearly circular but with the adjacent inner margins almost straight, and have each a circular central orifice. On the ventral surface of the anal segment is “a dark yellow chitinous plate showing six irregular paired tubercles ” ; this plate is surrounded by an area of rather coarsely granulated skin. Pupation takes place in the ground beneath the dung, at a depth of from half to three-quarters of an inch in the case of larvae in dung lying on fine sand. The puparium, or pupa-case, is of the normal Muscid type, dark brown in colour, barrel-shaped, and from 4 to 4.5 mm. in length, by 2 to 2.5 mm. in width. It is probable that Lyperosia does not often Lyperosia attack man, at any rate when it can get access and Disease, to domestic animals or big game, and it is not likely that flies belonging to this genus will prove to be disease-carriers among human beings. With regard to Lyperosia and animal trypanosomiases very little can yet be said, and for Africa at any rate there is no experimental evidence available. As has already been stated, Montgomery and Kinghorn have recently expressed the opinion that in North-Western Rhodesia at the present time trypanosomiasis is disseminated in herds of * Cf. Riley, C. V., and Howard, L. O., “The Horn-Fly (Hcematobia serrata, Robineau-Desvoidy) ” [—Lyperosia irritans, Linn.]: Insect Life, Vol. II., pp. 93- 103, Figs. 11-15 (1889). M