3t) PRIZE ESSAY : 



ORDER X. 

 Aphamptera. (Aphanes, inconspicuous ; ptera, wings.) 



57. Fleas are emblematic of this order. It is said that com- 

 mon fleas (pulex irritans) not unfrequently lay their eggs under 

 the toe-nails of uncleanly persons ; the larvse is white and active, 

 acquires maturity in a fortnight, and spins for itself a cocoon in 

 which it assumes the pupa states. The tropical chigo, is a much 

 dreaded pest in hot countries. 



ORDER XI. 

 Thysanoura. (Thiazo, to dance ; our a, tail.) 



58. Insects belonging to this order are often found on the sur- 

 face of water in summer and on snow in winter. In Pennsylva- 

 nia vast multitudes of a certain species were noticed in February, 

 1849, covering the snow for about a quarter of a mile with a 

 breadth of several rods. The species was probably the Podura 

 nivicola, one not uncommon in Canada. 



ORDER XII. 

 Parasita. 



59. This order embraces the disgusting parasitical insects call- 

 ed lice. The pediculus capitis, infests the human head. Leen- 

 wentrock, actuated by a desire to acquire information respecting 

 the habits of this insect, kept a male and female louse in his 

 stocking for eight weeks. He ascertained that in that short 

 space of time they might increase to five thousand. A species of 

 parasite is found infesting the human body in connexion with a 

 dreadful disease of the skin, named Phthiriasis. Many historical 

 names are associated with this terrible infliction ; among them 

 we find those of Herod, Plato, Antiochus, Epiphanes, and the 

 Emperor Maximilan . 



