The Mosquitoes of New Jersey 15 



other than certain ones connected with reproduction, and apparently 

 they are not necessary in elementary classification. 



Each leg consists of a small coxa and trochanter which, in figure 

 3, are sohiddenby thebodyasnotto show, a long femur, and equally 

 long tibia, and a 5- jointed foot, or tarsus. The last joint is tipped 

 with claws. 



The wings have scales, generally collected along the veins. The 

 color and arrangement of the scales determine the uniformity or 

 spotted appearance of the wings. 



When an infesting brood has been analyzed and traced to the 

 place of origin as nearly as possible, it then becomes necessary to de- 

 termine what species of wrigglers are found in the pools. If the 

 species thus determined prove identical with those of principal mem- 

 bers of the brood on the wing, the proof of source is complete. 

 Furthermore, when wrigglers are found, it is not possible to judge 

 whether they need treatment unless the kind of mosquitoes which 

 they will produce is known. We must, therefore, be able to recog- 

 nize the larvae as readily as the adults. To enable vis to do this 

 the external features must be discussed. 



Like the adult, the wriggler exhibits the three divisions of the 

 body — head, thorax and abdomen. The head bears a pair of eyes, 

 a pair of antennae, and rotary mouth brushes. Each antenna ex- 

 hibits a small bunch of hairs which has been designated as the an- 

 tennal tuft. The thorax has various tufts of bristles scattered over 

 it, known as the thoracic tufts. The abdomen consists of eight well- 

 developed segments, each of which bears some tufts of bristles, 

 known as the abdominal hair tufts. The eighth segment has grown 

 a process known as the anal tube, or siphon, which bears a double 

 row of spines on its posterior surface and has the opening of the 

 breathing system at its tip. In nearly all species this tube is used to 

 penetrate the water surface-film and to reach the atmospheric air. 

 The ninth segment is small, bears a large group of bristles, the anal 

 tuft, and some smaller tufts. The anal opening is situated at the 

 outer end of this segment and the tracheal gills extend outward from 

 this opening. On each side of the eighth segment there is a little 

 patch of scales that is much used in classification. 



For the determination of species of mosquitoes some sort of ar- 

 tificial key is necessary. The one which follows was prepared by 

 Harry B. Weiss and Raymond S. Patterson. It has been used in 

 the writer's classes for a number of years and has been found rather 

 satisfactory. It has the fault, however, of not making adequate dis- 



