32 



finally extinguishes them. On very cold days they are not 

 aggressive." 



Mr. H. H. King has recently published an interesting account 

 of the habits and life-history of Simulium griseicollis, with coloured 

 illustrations of the different stages, based on observations made 

 by him in the Dongola Province, in December, 1906, and January, 

 1907.* The larva of S. griseicollis, which is described by Mr. King 

 as " ashy grey to greenish in colour," and about 5 mm. in length 

 when adult, exhibits no specially distinctive external features, 

 but, like the larva of S. damnosum, Theob., is apparently provided 

 with well-developed protrusible tracheal gills on the last segment. 

 " The pupa," writes Mr. King, " is pale chestnut brown in colour 

 and is enclosed in a semi-transparent, brown, pocket-shaped cocoon, 

 about 3 mm. in length. Projecting above the edge of the cocoon 

 is a pair of white to greyish white respiratory appendages. Each 

 appendage consists of three leaf -like processes, two of which are 

 united at the base." It may be remarked that the trilobate, leaf- 

 like form of the respiratory appendages of the pupa of S. griseicollis 

 is strikingly different from the branching filamentous type, seen in 

 pupse of European and North American species of Simulium. 



Mr. King, after remarking that " During certain seasons of the 

 year, vast swarms of the little sandfly Simulium griseicollis locally 

 known as Nimitti occur in the northern parts of Dongola Province," 

 describes the " Life-history and habits " as follows : 



" The larval stage of the Nimitti is passed in the swiftest running 

 water, the eggs probably being deposited in masses on rocks and 

 plants at the water's edge. 



" The larvae, though aquatic, are poor swimmers, so attach 

 themselves to some fixed support and rely on the current to bring 

 their food to them. They are usually particularly numerous on 

 debris e.g., sticks and weeds caught up among rocks. On 

 their support they spin a network of silken threads by means of 



* Cf. H. H. King, " Third Report of the Wellcome Research Laboratories at the 

 Gordon Memorial College, Khartoum " (London : Bailliere, Tindall & Cox, 1908 

 [February, 1909]), pp. 206-208, Plate XXXIII., figs. 1, 2, 4 & 6. King's figure of 

 the perfect insect, which has apparently been taken from a denuded specimen, is, 

 unfortunately, misleading as regards the coloration of the body. 



