5 6o 



THE ANIMAL PARASITES OF MAN 



usually six in number (in one genus seven) ; the costal vein carried round the border 

 of the wing. 



(2) Head, thorax and abdomen usually, but not always (Anopheles, etc.), covered 

 with scales. 



(3) Mouth parts formed into a long piercing proboscis. 



As a rule the males may be told from the females -by their antennas being 

 plumose, whilst in the females they are pilose (vide fig. 394), but this does not 

 invariably hold good, for in Deinocerites, Theobald, and Sabethes, Desvoidy, and 

 others, they are pilose in both sexes. The labial palpi are very variable in regard 

 to their form and the number of segments ; in the Anophelina they are long in both 

 sexes, as long or nearly so as the proboscis, more or less clubbed in the males ; in 

 Citlicina, Joblotina and Heptaphleboinyia, they are long in the males, short in the 

 females ; in sEdeomyina, short in both sexes. 



Scales. The most important structural peculiarities in Culicidce are the scales, 

 which form the chief and most readily observed characters for separating genera 

 and species. The importance of scale structure has been recently ignored by some 



FlG. 398. Neuration of Wing. Explanation of Wing, Veins and Cells. A, costal cell ; 

 B, sub-costal cell ; C, marginal cell; D, first sub-marginal cell (= first fork cell) ; E, second 

 sub-marginal cell ; F, first posterior cell ; G, second posterior cell(=: second fork cell) ; H, first 

 basal cell ; I, second basal cell; J, third posterior cell; K, anal cell; L, auxiliary cell; 

 M, spurious cell ; c, costal vein ; 1st 6///, first to sixth longitudinal veins ; a, a and a", incrassa- 

 tions (a 1 called by Austen the sixth vein, a" the eighth vein); y, supernumerary cross vein; 

 z, mid cross vein ; /, posterior cross vein ; s.c., sub-costal. (Theobald.) 



workers, who are probably right academically, but as a means of separating groups, 

 and so more easily running down a species, the practical man is strongly advised to 

 follow this method. As to what a genus is, is purely a matter of personal opinion. 

 If one examines any recent standard work on entomology one will find a species 

 being placed in varied genera by the varied authorities. 



The head, thorax, abdomen and wings are in nearly all cases clothed with 

 squamee of varied form, of which the following are the main types (fig. 397) : 



(1) Flat, spade-shaped scales (a). 



(2) Narrow curved scales (e). 



(3) Hair-like curved scales (d). 



(4) Spindle-shaped scales (/). 



(5) Small spindle-shaped scales (). 



(6) Upright forked scales (h] and (z'). 



(7) Twisted upright scales (7). 



(8) Inflated or pyriform scales (k). 



