76 THE FLEA [OH. 



The chigoes and their allies are of special interest 

 for more than one reason. The females are to a 

 greater or less degree stationary ; they fix themselves 

 firmly to their hosts and become veritable parasites. 

 Several of the earlier zoologists believed that the 

 animal was a mite; and it is somewhat remarkable 

 that Oviedo himself should have so promptly detected 

 the relationship of the insect he saw with the fleas. 

 By reason of the parasitic habits of the females, more 

 is known about their appearance and life than in the 

 case of the more active males. In some species the 

 males remain, for the present, quite unknown: and 

 not very much is recorded about the early life-history, 

 eggs, larvso and pupae of either sex. The parasitic 

 habits of the chigoes and other allied fleas lead one 

 to expect peculiar modifications of form such as are 

 usually to be observed when an animal passes from 

 an active to a stationary life. These modifications 

 are the more easily understood as the various species 

 are not all stationary to the same degree. It is fairly 

 plain that this family of fleas is a development from 

 the less specialised and less parasitic family Pulicidce. 

 In fact the gradual development of the organs from 

 a generalised to a more specialised stage is strikingly 

 shown in these insects. To follow this in detail would, 

 however, require a very minute and technical know- 

 ledge of their form. 



The chigoe family is so well characterised that 



