[It is seldom that more than one larva is found in each individual. It is generally found in the arm and leg, but now and then the face. The perfect insect has never been bred from a larva removed from a human being, so that there is still uncertainty as to the actual species. D. cyaniventris is 11 to 12 mm. long, has an ochraceous buff-coloured face, dark grey thorax, metallic dark blue to purple abdomen, and brownish wings. D. noxialis is somewhat larger.
[In the Journal of Tropical Medicine and Hygiene, January 15, 1905, viii, p. 23, reference is made to this Oestrid in Trinidad, where it is called the “mosquito worm.” One case here recorded showed no fewer than four worms on the chin and one on the hand. It is here stated that the fly never attacks man or animals directly, as it is said to do by Scheube, but that the eggs are deposited on leaves and branches in wooded lands and forests, and thus man, hunting dogs and wild animals in passing through get the larvæ deposited on them accidentally. The affection is common in Trinidad. Mention is made that a little 1 in 40 carbolic lotion syringed into the aperture in the skin over the worm quickly killed it.
[The cattle worm, or founzaia ngómbe, is the name given to a larva which develops beneath the skin of oxen and men in Central Africa, especially amongst the natives and stock of Unyamonezi. According to P. Dutrieux, the egg is laid by a large fly that accompanies cattle. It is unknown between the central plateau or the Ugogo and the East Coast.—F. V. T.]
Cavicolous Oestridæ.
The forms belonging to this group inhabit as larvæ the nasal and frontal sinuses of ruminants, Equidæ and Proboscidæ, which they leave for the pupal stage. The larva of—
Genus. Oestrus, Linnæus,
Oestrus (Cephalomyia) ovis, L.,
occurring in sheep, has also been observed in man in six cases in the nose and larynx (Saitta in Gaz. d. Osp. d. Clinic, 1903, No. 128). So far as is known, the eggs are deposited in the nasal cavity.
[Oestrus ovis frequently occurs in man. MM. Sergent (Ann. de l’Inst. Pasteur, 1907, pp. 392–399) mention that they lay their ova on the noses, eyes and mouth of humans in Algeria whilst flying, but that they disappear after three to ten days or the inflammation produced by them. Portschinsky (Mem. Bur. Ent. Sci. Com. Cent. Bd. Land Adm. and Agric., 1913, x, No. 3, p. 63) also gives cases. He doubts that ova are laid on the nose; evidently the Russian habit is anomalous, for the Sergents, Collings and myself find ova laid as a common occurrence. I have often seen them on the nose of sheep. This fly also occurs in the Argentine (Serres, in Gaceta Rural, April, 1913, vi, pp. 759–761).
[The tamné or thimni of the Kabyles, a human myiasis of the Tuareg mountains in the Sahara, is caused by Oestrus ovis. Here the larvæ are said to be ejected on to the conjunctival and nasal mucous membrane of humans.