48 MORE MINOR HORRORS 



closed tube. It receives at its base the products 

 of the saHvary glands of the mosquito, and it 

 is these products which contain the organisms 

 which cause malaria — a disease which has 

 probably caused more trouble and has played 

 a greater part in the history of the world 

 than any other malady to which humanity 

 is heir. Down this minute, microscopic groove 

 has flowed the fluid which has closed the 

 continent of Africa for countless centuries 

 to civilisation, and which has played a domi- 

 nating part in destroying the civilisations 

 of ancient Greece and of Rome. 



When the adult mosquitos (the imagines) 

 leave their pupa- cases they are unable to pierce 

 the human skin until the mouth parts have 

 hardened, and this takes at least six hours. 

 In England they can undoubtedly feed 

 twenty-four hours after leaving the pupa-case. 

 When feeding, both the sensory antennae and 

 the tactile maxillary palps are thrust forward 

 at right angles to the proboscis. They thus 

 test the place where the two-lobed extremity of 

 the labium will guide the battery of stylets into 

 the substance they are feeding on. The female 

 is much more voracious than the male, which, 

 as we have mentioned above, cannot pierce 

 the human integument, and has to be content 

 with a vegetarian diet. Sometimes the effort 

 even of the female mosquito to insert its 



