SIMULIIDAE OF AFRICA 105 



bare. Fore tarsus slender, fore basitarsus 6-75-8-5 times as long as its greatest breadth. $ : 

 cibarium toothed between cornuae. Tarsal claws with minute pointed basal tooth. Scutum 

 pale ashy grey with three broad dark vittae. Abdomen patterned, pale grey pruinose with 

 three blackish brown longitudinal bands formed by subquadrate dark marks on dorsum of seg- 

 ments 3-5 and median dark vitta extending to tergites 6 or 7. Seventh sternite well developed, 

 rather strongly haired. Gonapophyses slightly produced and rounded, concave on inner 

 margin. Paraprocts normal or slightly produced downwards. Spermatheca without definite 

 pattern or internal hairs, q* : scutum with black and silvery pattern, sometimes a broad black 

 median band with shorter broad black sublateral vittae that more or less merge with median 

 vitta, sometimes extensively black with silver shoulder marks and greyish pruinose sides and 

 hind margin. Genitalia with very large heavy elongate subparallel-sided styles and short 

 broad coxites, style very much longer than coxite and with one apical spinule ; ventral plate 

 small and Y-shaped with toothed and haired body and widely divergent basal arms, without 

 beak-like process in profile ; median sclerite elongate subovate, sometimes acuminate basally 

 and usually widened and slightly cleft apically ; parameres large, elongate subtriangular, para- 

 meral hooks very numerous. Pupa : Gill filamentous, 6 or 8 long slender filaments arising near 

 base and directed forwards, gill shorter than pupal body. Abdominal onchotaxy normal, fourth 

 segment ventrally without supernumerary hook each side, segment 2 dorsally with three or four 

 minute spinous hooklets each side, a few long hairs on the segments laterally and lateroventrally ; 

 dorsal spine-combs only on segment 8, only few stout spines either side on well sclerotized band. 

 Cocoon shoe-shaped, fenestrate anteriorly and especially on neck, the openings numerous and 

 irregular. Larva : Head and cephalic fans normal. Hypostomium with usual nine apical 

 teeth, median and corner teeth moderately to strongly prominent ; 6-1 1 setae in each hypo- 

 stomial row, rows rather divergent posteriorly from lateral margins of hypostomium. Head 

 with extent and intensity of pigmentation varied, head-spots very indefinite but areas where 

 spots normally occur generally paler than surrounding areas, pattern apparently therefore 

 essentially negative. Postgenal cleft large, very much longer than postgenal bridge, subtri- 

 angular with rounded tip or broadly sagittate and sharply pointed anteriorly. Mandible normal, 

 first comb-tooth very large and subequal to one of the outer apical teeth, second and third 

 comb-teeth small and short and subequal or second shorter than third, second and third comb- 

 teeth very much shorter than and strikingly differentiated from succeeding long fine comb-teeth ; 

 two mandibular serrations. Antenna of medium length (slightly longer than stem of cephalic 

 fan), with four segments, occasionally appearing to have fifth segment through differential 

 pigmentation of second segment. Thoracic cuticle bare. Abdomen widening gradually to 

 sixth and seventh segments, widest well before circlet. Abdominal cuticle bare. Ventral 

 papillae absent. Accessory sclerites absent. Rectal scales present. Rectal gills usually with- 

 out secondary lobules, rarely a few thumb-like secondaries near base of each main lobe. Post- 

 erior circlet with 70-100 rows of 11-19 hooks. 



Distribution. Southern parts of the Palaearctic Region, from Spain through 

 Mediterranean Europe to Transcaucasia, Soviet Central Asia, Afghanistan, Kashmir, 

 Tibet and Sinkiang ; also North Africa (Morocco and Algeria : Map n). 



Discussion. The small subgenus Tetisimulium is a distinctive group in the 

 Simulium s.l. fauna of the drier, most southerly, areas of the Palaearctic mainland, 

 the females being very easily recognized by the pale greyish pollinose scutum with 

 its three broad dark longitudinal lines (pattern usually much as in Text-fig. 73) and 

 by the pale grey abdomen with three lines of large dark spots. The large abdominal 

 tergites 6-8 of the female, which in the subgenera Simulium s. str. and Odagmia are 

 rather shining polished black or black-brown, are entirely pollinose in Tetisimulium 

 females and usually pale grey with or without a darker median line, and the abdom- 



