THE GENERAL STRUCTURE OF A LARVA. 



For the purposes of this Key it is only necessary to draw attention to 

 those parts of the head, thorax, or abdomen, of the larva, which will be taken to 

 illustrate the specific differences" If these parts are absent from any larva which is 

 being examined, the larva is not anopheline, however much it may have looked 

 like one to the naked eye. 



THE HEAD. 



The head of every anopheline larva is adorned anteriorly by three 

 pairs of hairs, called the clypeal hairs, the anterior -external, the anterior- 

 internal, and the posterior, (see for example Plate I, figures l&2,);they will 

 be referred to hereafter simply as external, internal, posterior. 



The antenna in certain species bears on its inner side a strongly 

 branched hair, (see Plate VII.). 



THE THORAX. 



Over the promontory of the thorax are groups of hairs, called the 

 anterior thoracic hairs, (see Plate I, figures 1A, 2A.). 



THE ABDOMEN. 



On certain segments of the abdomen are borne laterodorsally a pair of 

 fan - shaped hairs called the palmate hairs, (see for example Plate III, figures 

 1A, 2A,). This is with the exception of the species umbrosUS, which is remarkable 

 in that it does not possess any palmate hairs, a fact which Stanton was the first 

 to discover. 



* Christophers has observed that for the use of a key the most unvarying structures should 

 be taken. "Where therefore any possibility exists for confusion to arise in the following descriptions, from any 

 "inherent variability" of the forms given, an alternative structural point will be given in a footnote. 



