

PLATE xn 



Figure 1. The labella of Haematobia stimulans, drawn from a 

 cleared preparation, fl., the flaps, on the internal sur- 

 faces of which are to be found the pseudotracheae. 

 p.b., the position of the petiolated blades, p.s., the 

 position of the pseudotracheae, in the resting condition, 

 m.f., the upper division of the fork of the mentum, on 

 which rests the furca. m., the mentum. x 150. 



Figure 2. The discal sclerite of Philaematomyia lineata. t.p., 

 the flange which projects from the distal ends of the 

 labellar rods, and to which the teeth are attached, 

 x 470. 



Figure 3. The discal sclerite and distal end of the labial gutter 

 of Stomoxys calcitrans. m.g., the median portion of 

 the gutter. The commencement of the keel is shown. 

 The teeth are attached by a strong but flexible band of 

 fibres to the concave distal end of the sclerite. X 450. 



Figure 4. The lower end of the pharynx of Haematobia 

 stimulans, seen from behind, to show the nature of the 

 wall of the buccal cavity, r., the rings of chitin which 

 surround the tube, x 350. 



Figure 5. The teeth and connected structures of Haematobia 

 stimulans, detached from the discal sclerite. x 525. 



Figure 6. An isolated tooth, (Haematobia stimulans) to show the 

 secondary teeth on its inner surface. These secondary 

 teeth become external when the teeth are everted. 



