EXPLANATIONS OF PLATE I. 



Fig. 1. Side view of head of Culex rufus, with extended mouth-parts; 

 a, antennae. 



Fig. 2. Same from above with mouth-parts partly cut away. 



Fig. 3. Tip of labium of female Culex. 



Fig. 4. Tip of labium of male Culex. 



Fig. 5. Tips of separated setae of mouth-parts of Culex. 



Fig. 6. Tip of labrum-epipharynx seen from beneath and in section. 



Fig. 7. Cross-section through the labellae and tip of labium of female Culex. 



Fig. 8. Cross-section near the middle of the proboscis of female Culex. 



Fig. 9. Cross-section through pharyngeal region of the forward part of the 

 head of female Culex. 



Fig. JO. Cross-section through the posterior part of the head of female 

 Culex, to show the sucking bulb of the oesophagus, b, lumen of 

 the oesophageal bulb, bm and 6m', .muscles to dilate the bulb. 

 r, chitinous rods which support the oesophageal bulb, rm, retractor 

 muscles of the maxillae, at their point of origin, t, elastic plates of 

 sides of bulb. 



Fig. 11. Longitudinal section of the head of a female Culex. b, oeso- 

 phageal bulb, g, point where the clypeus appears cut off from the 

 rest of the head, v, valve between pharynx and oesophagus. 



Fig. 12. Cross-section near the middle of the proboscis of a male Culex. 



Fig. 13. Cross-section at the base of the proboscis of a male Culex. 



Fig. 14. Cross-section further into the base of the proboscis of a male Culex. 



Fig. 15. Cross-section through the pharyngeal region of the head of a male 

 Culex. 



