SIMULIIDAE OF AFRICA 109 



but not all forms of Simulium s. str. by the constant possession of a small spinule- 

 like tooth at the base of the female claw, by the presence of eight gill filaments that 

 almost always branch in regular pairs, by the non-fenestrate cocoon, and by the 

 much smaller postgenal cleft and usually simple rectal gills of the larva. These 

 same characters distinguish Odagmia from Gnus Rubzov, a name that Rubzov and 

 Stone apply to a genus-group segregate that they consider distinct from Simulium 

 s. str. but which is here treated as a synonym of the latter (for further discussion of 

 the status of Gnus see under Simulium s. str. below). 



The Odagmia segregate is not represented in the Simulium fauna of the New World 

 and does not, in the Old World, extend into the Oriental Region : Puri (1932a) saw 

 two specimens with haired pleural membrane, identified by him. as ornatum Meigen, 

 supposedly collected at Cannanore in South India, but considered that there must 

 have been an error of labelling (this is probably true, as later collections of 

 Simuliidae from the Oriental Region have not revealed the presence of ornatum-\\ke 

 forms in the area). In the Mediterranean area, including the Canary Islands, 

 Morocco, and the Middle East, species of Odagmia form a main component of the 

 Simulium s.l. fauna, and in many parts are the only species present in the fauna in 

 which the adults have the basal section of the radius bare (most of the black-fly 

 communities of the southern Mediterranean areas are comprised by forms of the 

 subgenera Etisimulium and Wilhelmia in which the adults have the radius entirely 

 haired). 



The Canary Islands are the type-locality of three supposed species belonging in 

 subgenus Odagmia, viz. S.{0.) intermedium Roubaud, 1906 ; S.(0.) H -nigrum 

 (Santos Abreu, 1922) ; and 5.(0.) insolitum (Santos Abreu, 1922). No immature 

 stages of any Simuliidae have yet been collected in the Canary Islands and this makes 

 it difficult to recognize the specific identity of forms described from there with any 

 reliability, but it appears almost certain that some or all of these names are synony- 

 mous either with S.(0.) ornatum Meigen or S.(0.) nitidifrons Edwards, which occur 

 widely in western Europe and (nitidifrons particularly) in North Africa from Morocco 

 to Tunisia : insolitum, H-nigrum, and intermedium from the Canaries are all based 

 on unique female holotypes that have the frons semi-shining (as in nitidifrons) and 

 the legs rather extensively pale, and appear to be conspecific with each other and 

 also with shining-frons forms of Odagmia from the North African mainland identified 

 in the literature as nitidifrons (Edwards, 1923 ; Grenier, 1953 ; Grenier & 

 Theodorides, 1953 ; Grenier, Faure & Laurent, 1957). Simulium egregium S£guy, 

 1930, based on a female holotype from Morocco, is probably also the same, but no 

 re-examination of the type has been made since the original description. 



Finally, it may be useful to enumerate the main characteristics that Odagmia 

 shares with Simidium s. str. ; basal section of radius bare, fore tarsus dilated, katepi- 

 sternum bare, minute denticles or nodules on cibarium between cornuae, similar 

 adult abdomen in both sexes, same form of male hypopygium with heavy elongate 

 styles and complex toothed ventral plate, filamentous pupal gill, similar larval 

 mandibles and larval body shape, bare larval cuticle. 



Included taxa. All forms with haired pleural membrane forming the ornatum- 



