I 9 2 



or one-sixth objective : the following points can be 

 readily made out. Observe that old larvae are often 

 almost totally enveloped in Vorticella or other In- 

 fusoria. 



1. The Head. The head is globular in shape, 

 and is for the most part enclosed in a hard and con- 

 tinuous chitinous case. Anteriorly, there are the 

 rather complicated mouth parts. Posteriorly, there is 

 an opening into which the neck is inserted, around this 

 is a pigmented border resembling a collar. There is 

 a gap in this dark border in the middle line posteriorly, 

 and here two diverging bands of chitin form a ' V ' on 

 the back of the head. Grouped around this V ' mark 

 are more or less continuous patches of pigment, which 

 shew differences in their arrangement, to seme extent, 

 specific. 



2. The Antennae. Arise from two prominent 

 lateral protrusions, they are freely movable at their 

 articulation. Each antenna is a rod-shaped unjointed 

 body. At its termination are two leaf-shaped bodies, 

 and a branched hair arises between the leaflets. The 

 antenna is covered with small spines, which are 

 particularly developed in pairs along the inner border. 

 In most species of Atwpbelines a hair can be made out 

 arising from a papilla situated at the junction of the 

 proximal and middle third of the antenna. 



This hair is of specific importance. 



(i) In the majority of Anophelines it is simple 

 and unbranched. 



(ii) In A. lindesayi, M. nigerrimus, M. bar- 

 birostris it is branched, and in the last two very large 

 and conspicuous (Fig. 63). 



3. The Eye.^-In the full-grown larva a crescentic 

 compound eye is seen on either side, and behind this 

 a single pigment mass (simple eye). 



