PLATE III, 



Fig. 1. Longitudinal section of head Culex tseniorhynchus ; after 

 Macloskie. oe, oesophagus ; cl), cerebrum ; m, muscle ; n, 

 nerve commissure ; du, venomo salivary duct ; Ir.e, labrum 

 epipharynx. 



2. Venomo salivary duct of the same, with upper nest of 



glands ; after Macloskie. sg, salivary gland ; i)g, poison 

 gland. 



3. Head of ^Eschna heros ; front view ; after Packard. 



4. Foot of Musca domestica ; X 200 ; after Eombouts. 



(184) 



