SIMULIIDAE OF AFRICA 29 



between the more advanced Simuliini and the more generalized Prosimuliini) come 

 much closer to the Simuliine type than to the Prosimuliine type, although slightly 

 intermediate : the sulcus is sharply defined laterally, deep though rather wide, and 

 is almost complete anteriorly, and the katepisternum in side view is normally 

 distinctly longer than its depth. This character therefore fits Simuliini rather than 

 Prosimuliini. Other characters tending towards Simuliini are shown by the 

 maxillary palp (in which the last segment is elongate and as a rule much longer than 

 the third segment, as in Simulium s.l.), and by the pleural membrane : in almost all 

 species of Metacnephia the pleural membrane is conspicuously haired as in many 

 Simulium, whereas (to the best of my knowledge) the pleural membrane is bare in 

 all Prosimuliini — though here it should be noted that some specimens of Gymnopais 

 dichopticus Stone may show a very few strange stiff black setulae on the membrane, 

 and there are a few hairs on the upper sclerotized part of the mesopleuron (just 

 below the scutal ridge) in Prosimulium morotoense (McCrae & Prentice). 



The balance of characters in Metacnephia taken together make it best to assign the 

 genus to Simuliini, a course which seems particularly proper when the ovtshinnikovi- 

 group is taken into consideration, for this little known aggregate of species from 

 Transcaucasia, Soviet Central Asia and Siberia has a combination of characters 

 some of which are those of Metacnephia and others of Simulium s.l. (Rubzov, 1959- 

 1964, defines the ovtshinnikovi species-group and places it in Cnephia). The 

 ovtshinnikovi-gvonp has a well developed and deep pedisulcus, has the pleural 

 membrane bare, sometimes has the katepisternum haired, lacks a definite basal cell 

 in the wing, and has the pupal abdomen without complex anchor-like hooklets and 

 in all of these characters differs considerably from Metacnephia ; on the other hand 

 the larval stage is not distinguishable from that of Metacnephia and has, for instance, 

 the same type of elongate postgenal cleft, similar hypostomium and mandibular 

 serrations. Since the adult and pupal stages are not adequately separable from 

 Simulium s.l., it is considered that the ovtshinnikovi-group would be better assigned 

 to this genus, and the group is therefore excluded from Metacnephia as here defined : 

 in my view, it has no close affinity at all with the true Cnephia Enderlein (even less 

 than Metacnephia) and Rubzov's assignment of the group to this genus-group name 

 is inapt. 



The species of Metacnephia almost all have the pleural membrane thickly haired, 

 but there are a few species in which it is apparently naturally bare : it is haired in 

 all North American species except M. saskatchewana (Shewell & Fredeen) (this 

 species has not been seen but the original description states ' mesopleural membrane 

 bare '), and the majority of Palaearctic species, but not in M. persica (Rubzov) ; 

 although Rubzov (1959-1964 : 212) places persica in his key-isolate 9 (42) in which 

 the pleural membrane is stated to be haired (' Membran behaart '), his own original 

 description of this species (Rubzov, 1940 : 495) states that the membrane is bare, 

 and this has been confirmed from material seen. 



The species assigned here to Metacnephia are moderately homogenous and the 

 genus is not divided into species-groups. One included species, M. pedipupalis 

 (Rubzov), is atypical however in the characters of the cocoon and does not conform 



