1 8 4 



ELEMENTS OF PHYSIOLOGY 



not often have the jungle fever, so fatal to Europeans who 

 have not become "acclimated" that is, whose blood has 



FIG. 157. Mosquitoes. Comparison of 



The Non-malarial Genus Culex. 

 Palpi short. 

 Wings not spotted. 

 Legs sometimes spotted. 

 Position at rest, parallel to surface. 



Larva, or wiggle-tail, breathes, and rests 

 perpendicular to surface of water. 



The Malarial Genus Anopheles. 



Palpi long. 



Wings sometimes spotted. 



Legs not spotted. 



Position at rest with abdomen and hind 

 legs elevated at an angle to surface. 



Larva, or wiggle-tail, is parallel to sur- 

 face of water when it breathes. 



The sucking tube and feelers are long in both genera. The long palpi of the malarial genus 

 furnish an infallible sign. The palpi are found on each side of the sucking tube. The 

 feelers are next to the palpi. 



not developed the antitoxin which kills the germs caus- 

 ing jungle fever. It has been shown that the mosquito 

 is probably instrumental in transmitting yellow fever. 



319. Antitoxin Treatment. If the toxins from diph- 

 theria germs, grown in suitable material, are injected into 



