Fig. 417.—Head of Glossina longipalpis, Wied. (After Grünberg.)
[This genus contains sixteen species,[423] all of which are confined to the Ethiopian region. Glossina may be distinguished from other allied genera by the proboscis, the antennæ, wings, and male genitalia. The proboscis projects forwards and has a swollen bulb-like base to the slender labium which holds the two structures, the needle-like epipharynx and the thread-like hypopharynx; the whole proboscis is ensheathed in the maxillary palpi. The antennæ have the first two segments small, the third large with a marked pore, the orifice of the sense organ near the base; from the base of the third segment also arises the three-jointed arista, the first two segments being, however, minute; the third bears a series of from seventeen to twenty-one fine branched hairs on one side. The male genitalia or hypopygium is more or less oval and tumid, its long axis lying in the antero-posterior direction, with a vulviform median groove (the anus) running from the anterior margin to beyond the middle.
[Newstead has shown the importance of the study of the genitalia in separating species (vide Bull. Ent. Res., ii, pp. 9–36 and 107–110, and iii, pp. 355–360; and Ann. Trop. Med. and Par., vii, No. 2, pp. 331–334).
Fig. 418.—Antenna of Glossina pallidipes, male. (After Austen.)
[The tsetse-flies reproduce differently from all other Muscidæ. The female produces at each birth a single full-grown larva, which is retained within the oviduct and there nourished by the secretion of special glands, and on being born crawls to some hiding place and at once becomes a puparium.
[The larva is a yellowish footless maggot nearly as large as the mother’s body, the skin shagreened and the anal extremity having a pair of large, black, granular prominences separated by a depression containing the breathing pores.
[The puparium is brown of various shades, the tumid lips of the larva being conspicuous, the size and shape of the lips enabling the puparia to be identified.