72 MOSQUITOES OF NOKTH AMERICA 



vague. In many cases intergrades between the different types of scales occur so 

 that the application of the terminology becomes necessarily a matter of opinion. 

 In fact the differences in the conception of these terms as employed by different 

 authors has brought about great confusion in the systematic literature. 



Part of the above terms are self explanatory, others can hardly be interpreted 

 without recourse to specimens. The wing-scales show the greatest diversity and 

 have been utilized the most and eleven of the types enumerated above, and their 

 modifications, are employed by Theobald as wing-characters. Along each wing- 

 vein there are two paired series of scales and the scales of these two series often 

 differ greatly in form and size. The non-biting Culicidge of the group Core- 

 thrinas show the most primitive condition of wing vestiture. In CJiaohorus the 

 scales along the wing-veins are long and hair-like and the two series are not 

 differentiated. Among the biting Culicidse the Anophelines show the most 

 generalized condition. In most species of Anopheles the scales along the veins 

 are narrow, lanceolate, and, while there are distinctly two series, the scales of 

 these series are often much alike. In other forms of Anopheles there is some 

 differentiation, the scales of the lower series being smaller, shorter and less 

 divergent. In Anopheles grabhamii the scales are much broader but of the 

 lanceolate character; irregularly scattered among these, and with a tendency 

 towards grouping, are larger and darker very broad scales, their apices broadly 

 rounded or subtruncate. These large, broad scales are the " Cycloleppteron 

 scales " of Theobald and are said by him to be inflated ; they are, however, flat 

 like other scales. 



The wing vestiture is remarkably diversified in Uranotmiia. On nearly all 

 the veins one of the series consists of small, truncate scales arranged in a single 

 row and overlapping. On the outer part of the wing the veins also have lateral 

 series of large scales and these differ in shape on some of the veins. Finally on 

 the basal portion of the fifth vein there is, in most species, a double series of very 

 broad small scales of a silver-blue color. In some species the scales on certain 

 parts of the wing are white. 



In Culiseta the wing scales are narrow and in two double series along the 

 veins. The lower series are of smaller shorter scales, closely applied to the veins ; 

 the upper series consists of long and very narrow outstanding scales. A very 

 unusual feature occurs in certain species of this genus; the anterior cross- vein 

 bears scales. In most species of Culex the appearance of the wing is similar to 

 Culiseta. There are, however, three double series of scales outwardly on some of 

 the veins. The long scales are usually narrow and blunt or truncate at the tip ; 

 these are the " linear " scales of Theobald, and we have termed these " ligulate." 

 In many forms the scales are broadened and rounded at their apices and there is 

 an increased tendency to crowding towards the apex of the wing. This con- 

 stitutes the so-called " Melanoconion scales " of Theobald ; however these are 

 not separable as a distinct type, but, through different species, intergrade with 

 the ordinary Culex scales, and the tendency to crowding towards the apex of the 

 wing is a very general one. The smaller scales when broad are often obliquely 

 subtruncate. In most species of Aedes the wing scales are entirely similar to the 



