148 MALARIA 



parasite of human malaria. Indeed, 14 different 

 species of Culex have been tried in this respect, and 

 in each case with negative results. The same nice 

 adjustment of parasite to host is found in Anopheles. 

 It will not convey the bird malaria, that is to say, 

 the gametocytes are destroyed in its body, but it is 

 readily infected by the human parasite, and at the 

 present date a considerable number of species have 

 been successfully tried, and this not only in Europe, 

 but in Africa, India, and the United States. 



Anopheles is obviously worth studying. It has now 

 been found very commonly distributed in England, 

 A. maculipennis abounding in the eastern counties. 

 Its boat-shaped eggs, laid, not as are those of the 

 genus Culex, in little rifts, but singly, give rise to a 

 charming little larvae, whose diet of minute algae gives 

 a greenish tint to the centre of the body, which else- 

 where is of a brownish hue. When at rest, these 

 small larvae float on the water parallel with the sur- 

 face, and not hanging down into the water as does the 

 larval Culex. They have a most beautiful arrange- 

 ment of minute hairs, arranged like the ribs of an 

 umbrella turned inside out, along the upper surface of 

 their backs, and by the action of these hairs they hang 

 on to the surface-film. Their breathing organs open 

 near the tail, but are not produced into the long 

 respiratory tube by which the Culex larva can be so 

 easily recognized. They possess the most marvellous 

 arrangements on the head for setting up currents con- 

 veying food to the mouth, and, in fact, they afford one 

 of the most charming objects of ' animated nature ' that 

 one could desire to watch. After some days, varying 

 in number according to the temperature, the larva 

 turns into one of those curious active Dipterous pupae 

 which are well known in the case of other gnats. 

 Like the larva, the pupa floats at the surface of the 

 water. When mature its integument splits along the 



