178 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



a variety of intergrading forms which are only distinguish- 

 able under the microscope. Some species have broader scales 

 upon the legs, mostly of lanceolate or spatulate form. They 

 may be keeled or terminate in fine points and their appear- 

 ance has suggested the term petaloid. When of light color 

 these scales are best seen on dry specimens, while the dark 

 scales become better visible in microscopic preparations. On 

 the mesouotum the scales are always narrow and rarely petaloid ; 

 in the latter case, however, they extend onto the frons and 

 clypeus and thus furnish a good character. Other characters 

 are the grouping of the scales into rows or tufts. The scales 

 of the legs may be already distinguished within the pupa 

 when the inclosed imago is well advanced. As they are 

 rather perishable good specimens always should be preferred 

 and can be told by the presence of the thoiacic vestiture. 



The males are generally so much like the females that they 

 can be associated without difficulty. They are always smaller 

 and sometimes distinguished by livelier color-ornamentation 

 and by hairier legs. Their claws are always three-toothed. 



With the claws of the females careful and repeated exam- 

 ination is necessary, because the secondary tooth is not obvious 

 and furthermore the projecting basal angle, or the tip of the 

 other claw, can be mistaken for the absent tooth. The tooth 

 is rarely absent, however, and on this account its presence or 

 absence constitutes a good specific character. 



Such painstaking work would result in discoveries any- 

 where; it is therefore not surprising that in a fauna as poorly 

 known as the South American the majority of the species 

 have proved to be new. Lutz, in his second paper, deals with 

 twenty-nine species, and of these twenty-six are described by 

 himself. Ten species, of which one is referred to the syn- 

 onymy in a supplementary note, are described on pupal char- 

 acters alone. They are forms of which the imagos are un- 

 known or have not been associated. It should be noted that 

 of the forms described in the imagx> the pupae of all but seven 

 are known. 



As a result of Lutz's endeavor to identify his specimens 

 with described species some synonymy has come about. Fol- 

 lowing determinations by Coquillett the names of two forms 

 described from remote localities are introduced into his first 

 paper, but abandoned afterwards. One of these is SimuUum 

 montanum, described by Philippi from Chile. The other one 

 is our North American Simulium venustiiiu. of which S.per- 

 tinax Kollar is made a synonym. Lutz was reluctant to 

 accept this synonymy, as the occurrence of the same species 



