18 THE FLEA [CH. 



Of the antiquity of fleas, and of the period in 

 geological history when the order made its appear- 

 ance, little can be said. When it was thought that 

 fleas were confined, as parasites, to warm-blooded 

 mammals and birds, evolutionists were inclined to 

 say that the parasites could not have appeared before 

 their hosts. The discovery of a flea on a reptile 

 opened the vista of possibly enormous antiquity 

 stretching back to Permian or Carboniferous ages. 

 The fossil record is most meagre. If we reject as too 

 doubtful the supposed remains of a flea from the 

 lower Oligocene strata at Aix in Provence, only one 

 undoubted fossil has been discovered. Nor does it 

 seem certain that fleas are entirely restricted to 

 preying on vertebrates. Dr Dampf introduced a 

 number of common bird-fleas (Ceratophyllus gallince) 

 of both sexes to some hairy caterpillars. He observed 

 that several of the fleas buried their heads in the 

 hairy covering of the larvae and remained some time 

 in the attitude of sucking blood. While this was 

 going on the victims made violent demonstrations of 

 annoyance and discomfort. He also observed that 

 a naked caterpillar was not attacked. 



Mr Boden has also recorded how he found in a 

 seed-warehouse some peas that were being eaten by 

 two species of Lepidopterous larvae. On bringing 

 these home and keeping them in a jar, he found 

 among them some small larvae which ultimately 



