16 



INTRODUCTION. 



It is, however, necessary for us now to reverse the pic- 

 ture, and to observe, that if insects are capable of being 

 serviceable to mankind, other species are not less injurious 

 to him and his property. We will first notice such species 

 as possess a direct influence against mankind. Of these the 

 various species of lice, the flea, jigger, and the bed-bug, are 

 pre-eminently obnoxious. Besides these, we are condemned 

 to suff"er from the occasional attacks of multitudes of other 

 species, which at all hours of the day cease not their tor- 



Gnat {Culex pipiens) female, natural size and magnified, with the head of the male. 



menting powers. Moreover, the hotter the clime, and the 

 period when the body requires the greatest portion of rest, 

 the more numerous are the hordes of our insect enemies. 

 The Tahani, Stomoxes, and Asili, are all highly irritating ; 

 but all these \deld to the gnat and the musqviito, which are 

 sometimes so annoying and so numerous, that their victims 

 have sunk under their attacks. They both belong to the 

 same natural group, CulicidcBj and as they breed in stag- 

 nant water and damp situations, it does not seem impro- 

 bable that the last-named insects were the species of flies 

 which were employed as one of the ten plagues of EgyjDt to 

 punish the rebellious Egji^tians. In the article Bat, in the 

 British Cyclopaedia, there is the following passage, which 

 especially bears upon the subject : — " The banks of the Nile, 



