1 6 Mosquitoes 



never very stiff. The first seven are usually much 

 alike, except for the fact that the lateral tufts grow 

 shorter in length as the joints approach the seventh. 

 In many species these segments are much the same, 

 but in others the general aspect of the abdomen is 

 very distinctive by virtue of the great length or num- 

 ber of the hairs, the presence of stellate tufts of hairs, 

 of palmate tufts, or of stiff bristles. On each side of 

 the eighth segment is a patch of scales, varying from 

 one row of four to eight scales to four or five rows of 

 as many as sixty-five scales. The number of scales in 

 the single-rowed species can be used as specific char- 

 acters, as they do not vary over two at the most, but 

 in the many-rowed species they will sometimes vary 

 as many as twenty, and cannot therefore be depended 

 upon in a table of species, as the two species falling 

 in the same couplet will not infrequently have, the 

 one 20 to 35 scales, the other 30 to 50 scales, or the 

 like. 



On the eighth segment is the breathing tube, 

 often referred to as the " anal tube " or " siphon " — 

 why the latter it is hard to imagine, as it is a siphon 

 in no sense of the word. It is very variable in length 

 and form in the different species, but, as a rule, the 

 relation of width to length is not a good character 

 upon which to depend in a key for the identification 

 of the species, especially when skins are to be named 

 or used as a basis for differentiation, as the cover 

 glass on the slide on which the skins are mounted 

 flattens the tube, making the relation quite different 

 in the exuviae from what it is in a whole larva. 

 When it comes down to employing such a slight 



