170 



MEDICAL ENTOMOLOGY 



27. Body grey or cinereous . . .... . . . . . . 28 



Body brown or black , ...'. , *i . 29 



28. 'Body grey with a white milky lustre, especially the pleura 



and pectus. Legs tawny, femora and tibiae with irregular 

 piceous bands, tarsi piceous. Length 2'5 mm. Hudson 

 Bay Territory'. This is a synonym of vittatum, Zett., 



according to Mr. Coquillett (1898) decorum. 



Thorax fuscous or cinereous pollinose, humeri pallid, pleura 

 pale cinereous, scutellum pale at the tip ; abdomen blackish ; 

 fore coxae pale, middle and hind ones cinereous ; femora 

 pale at the base, black at tip ; tibiae black. Length 3 mm. 

 Mexican species ........ cinereum. 



29. Abdomen somewhat shining, yellowish grey or whitish at the 



sides, and yellow at the base ; legs brown, tibiae and fore 

 coxae white, tip of tibiae and all tarsi black. European 

 species, also occurring in Greenland ..... reptans. 

 Basal segments of abdomen opaque, distal fore segments some- 

 what shining black or brown. Two long hairs at the tip of 

 the first and third fore tarsal joints 30 



30. Legs reddish yellow, tarsi black, except proximal half of 



middle and hind metatarsi which are light yellow. Length 

 2 mm. (St. Vincent Island). This is a synonym of pulch- 

 rutn, Phil., according to Hunter ..... tarsale. 

 Legs black, base of tibiae, first joint of middle and hind tarsi 

 and sometimes base of femora yellow ; extensor surface of all 

 the tibiae more or less whitish. A widely distributed and 

 varied species ......... venustum. 



31. Length 1'5 mm. Front and middle femora and tibiae wholly 



yellow ; hind ones, except apices, also yellow. Colorado griseum. 

 Length 2 '5 mm- Legs brownish black, distal part of femora, 

 base of tibiae, and greater part of metatarsi light yellow. 

 California argus. 



LUTZ'S KEY TO THE BRAZILIAN SIMULIIDAE 



1. Multicoloured species, the halteres and legs never entirely 



black 4 



Uniformly dark species, only the hair whitish, the wings 



colourless ............. 2 



2. The white hair thick but hardly visible to the naked eye .... 3 

 The white hair thick and clearly visible .... f lavopubescens. 



3. A little more than medium size, entirely black, from high alti- 



tudes , pernigrum. 



A little less than medium size, more of a chocolate colour ; not 



an aggressive species ....... hirticosta. 



4. Ground colour of thorax grey to black , 10 



Ground colour uniform .. . . . . . 5 



5. The sides of the thorax uniformly coloured 6 



The thorax black and gold, the marking varying . . . varians. 



6. Colouring vivid ............. 8 



Colouring dull .... 7 



