32 THE INSECT WORLD. 



There are other kinds of lice, but we will only mention the louse 

 which infests beggars and people of unclean habits, Pedicnius 

 humani corporis^ producing the complaint called phthiriasis. In the 

 victims of this disease these parasites increase with fearful rapidity. 

 This dreadful disorder is often mentioned by the ancients. King 

 Antiochus, the philosopher Pherecydes of Scyros, the contemporary 

 and friend of Thales, the dictator Sylla, Agrippa, and Valerius 

 Maximus, are said to have been attacked by phthiriasis, and even to 

 have died of it. Amatus Lusitanus, a Portuguese doctor of the six- 

 teenth century, relates that lice increased so quickly and to such an 

 extent on a rich nobleman attacked with phthiriasis, that the whole 

 duty of two of his servants consisted in carrying away, and throwing 

 into the sea, whole basketfuls of the vermin, which were continually 

 escaping from the person of their noble master. 



Little is known at the present day of the details of this complaint, 

 though it is observed frequently enough in some parts of the south 

 of Europe, where the dirty and miserable inhabitants are a prey to 

 poverty and uncleanliness — two misfortunes which often go together. 

 In Galicia, in Poland, in the Asturias, and in Spain, we may find 

 many victims of phthiriasis. 



Lice increase with such rapidity on persons thus attacked, that 

 it is common to attribute their appearance to spontaneous generation 

 alone. But the prodigious rapidity of reproduction in these insects 

 sufficiently explains their increase, especially when it is admitted that 

 it is possible for the female louse to reproduce young without the 

 agency of the male. 



The Thysanura or " Skip Tail " tribe are small insects, which are 

 better known on account of the beauty of their microscopic body 

 scales than. for any interesting habits or instincts. They do not 

 undergo metamorphosis. 



The Fish Scale or Lepisma saccharina, and the Skip Tail or 

 Podura plumbca belong to the Thysanura. 



