CHIRONOMID^E 579 



seasons, so much so that the natives have to leave their plantations. The bite 

 causes a weal, marked by a drop of blood. 



S. griseicollis, Becker. The so-called " nimitti " occurs in Upper Egypt and 

 the Anglo-Egyptian Sudan. It lives near the river and is not found more than 

 half a mile from it. Human beings are bitten on the face and hands, animals in 

 the region of the pudenda. 



S. latipes, Meigen. This is a European species, also found in Natal. 



S. wellmanni, Roubaud. The " ohomono " of Angola, where it bites viciously 

 and is dreaded by the naked porters. 



S. buissoni, Roubaud. Occurs in abundance in the Marquesas Islands. It has 

 been suggested that this species may help to propagate leprosy. 1 



A large number of these insects have been described by Lutz in Brazil.' 2 



A Simuliiun sp. (?) is very harmful to poultry in Cape Colony. 8 



In America, Simulida are most annoying. One, S. meridionale, Riley, also 

 known as the turkey gnat in the Mississippi Valley, has been supposed to be the 

 carrier of chicken cholera ; anyhow, it has caused the death of thousands of chickens 

 and turkeys in Virginia annually. 4 



In Mexico Townsend found a Simulium which was named S. occidentalism which 

 caused great annoyance to man, many people being so susceptible to them as to 



FIG. 401. Wing of Simulium. FIG. 402. Wing of Chironomus. 



preserve through the gnat season a chronic inflammation of the exposed parts of 

 face and neck, resulting from the repeated bites giving rise to sores. 5 



Men and horses have been partially incapacitated by the bites of sand-flies or 

 Simulium in a Hampshire wood (Cantlie, Brit. Med. Journ., April 28, 1900, 

 v, No. 2,052, p. 1023). 



Family. Chironomidae (Midges). 



The Chironomidce or midges are not only frequently mistaken for mosquitoes, 

 but some are very annoying to man by biting him as mosquitoes do. They are 

 easily distinguished from true mosquitoes (Culicidcz] by the following characters : 

 (i) head small, often retracted under the cowl-like thorax ; (2) no scales to the wings 

 or body; and (3) the different arrangement of veins on the wings (fig. 402). 



Two genera are important as annoying man, namely, Culicoides, Latreille, and 

 Johannseniella, Williston. The larvae of Chironomidcz are either aquatic, both 

 fresh water and marine, and help to make the former foul, 6 according to Slater, or 

 may, as in Ceratopogonince, live beneath the bark of trees, etc. The pupae are very 

 varied and also the life-histories of the different genera. 7 The blood-sucking habit 

 is confined to the sub-family Ceratopogonincc . 



1 Bidl. du Mus. d^Hist. naf,, 1906, xii, p. 522. 



' 2 Mem. Inst. Oswaldo Cruz, 1910, ii, fasc. 2, pp. 211-267. 



:! C. Fuller, "A New Poultry Pest," 1899, Leaflet No. i, Dept. Agric. 



4 Insect Life, 1888, i, p. 14. 5 Ibid., 1893, v P- 6l - 



" Entomologist, 1879, p. 89. " Theobald, "An Account of British Flies," i, p. 172. 



