475 



the host should be chloroformed, as this makes the fleas come out of the 

 hair and renders them sluggish in their movements. It does not as a 

 rule kill them, even if the host is killed, and they soon become sufficiently 

 active to escape if not caught. 



The nests of birds and mammals suspected to harbour fleas should be 

 brought to the laboratory entire, securely tied up in a cloth bag. The 

 contents are then spread out bit by bit on a large sheet of white paper, 

 and examined with a hand lens for larvae and pupae. The larvae, and 

 the imagines if present, are easily recognized by their movements when 

 the eye becomes accustomed to them. 



Fleas should be preserved in alcohol, or, what is better, mounted at 

 once. This is done by clearing them in caustic potash and mounting on 

 slides in Canada balsam. If fixed in alcohol first and subsequently 

 cleared for mounting the chitin is apt to become too much decolourized 

 and too transparent before the hardened internal organs are dissolved out. 

 Care should be taken in mounting them to spread out the legs so that 

 one of each pair can be seen distinctly. It is frequently necessary, in 

 order to identify the species with certainty, to dissect off the external 

 genitalia and mount them separately, and in doing this, as in all other 

 manipulations with fleas, the greatest care must be taken not to damage 

 the bristles, which are of so much importance in identification. 



When sending fleas to experts for identification some at least should be 

 sent in alcohol. It is essential to give the host's name and locality. 



Fleas for identification may be sent to 



The Hon'ble N. C. Rothschild, 



Arundel House, 

 Kensington Palace Gardens, 



London, W. 

 or to 



Mr. Carl Baker, 

 United States National Museum, 



Washington, U.S.A. 



LITERATURE 



BAKER, C. F. A Revision of American Siphonaptera, or Fleas, to- 



gether with a complete list and bibliography of the 

 group. Proceedings of the United States National 

 Museum, Vol. xxvii, pp. 365 469, Washington 

 1904. 



