52 



PRACTICAL PAEASITOLOGY 



it fails to find the opening by which it entered, the disc may be 

 removed from the funnel and the apparatus employed to catch other 

 specimens. Provided that they are kept sufficiently damp, mosquitoes 

 when caught may be kept for months in glass tubes closed with gauze. 

 V. Wasielewski describes a form of glass which appears to be very 

 useful for this purpose. It is a small glass cylinder, closed at one end 

 with a gauze cap, which is fixed by means of gum to a thickened rim 

 in the glass ; at the other end it is closed by a cork in which a hole 

 has been bored. Into this hole a small glass tube is fitted which must 

 not project inwards beyond the cork. It is furnished with a small 

 sponge which is kept wet. The mosquitoes are fed with blood through 

 the gauze cap. Culex takes three days to digest blood and then feeds 

 again ; Anopheles, which is more difficult to keep, is ready to feed 

 again on the second day, and should therefore be fed daily. 



FIG. 10. Head of Anopheles, a, Male ; 6, female. (After Giles, from Braun.) 



It is sometimes expedient to cultivate mosquitoes from larvae. 

 They are found on damp ground near water, the Culex in large or 

 small numbers, the Anopheles generally singly. Morphologically, 

 they are distinguished from one another by the structure of the 

 respiratory orifice, situated in the 8th abdominal segment. In Culex 

 it is placed at the extremity of a long breathing tube or syphon, 

 while in Anopheles no such breathing tube is present, the respiratory 

 orifice being situated in a minute depression upon the exact margin 

 of segments 8 and 9. The larvae are best reared in small aquaria, 

 which should be closed with gauze and protected from the sun and 



