23Q 



Examination of the Full-Grown Larva. — Cover 

 the larvae in a drop of water, with a coverglass, 

 and examine with one-fourth or one-sixth objec- 

 tive; the following points can be readily made out. 

 Observe that old larvae are often almost totally- 

 enveloped in vorticellae or other infusoria. 



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

 and is for the most part enclosed in a hard and 

 continuous 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 some 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 terminatian 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. Ano-^ 

 phelines a hair can be made out arising frgm a 

 papilla situated at the junction of the proximal and 

 middle third of the antennae. 



This hair is of specific importance, 

 (i) In the majority of Anophelines it is simple 

 and unbranched. 



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

 birostris it is branched, and in the last two very 

 large and conspicuous. (Fig. 55). 



