DIPTERA. NEMOCERA. 343 



the families only in a manner which may enable the 

 young student to refer species to them, is all that can be 

 attempted here ; and the readeF will find it necessary for 

 this to make himself acquainted with the figure of a 

 wing and its principal veins and cells given at the end of 

 the table of Diptera. 



The NEMOCERA have been divided into two families, 

 Culicidce, in which the proboscis is very long, and 

 Tipulida, in which it is short the Gnat (Culex) 

 being the type of the former, the Daddy Longlegs 

 (Tipula) of the latter. This marks off the Culex family 

 with distinctness, but the shortness or length of the pro- 

 boscis and membership of this family, are no certain 

 indications as to the blood-sucking habits of the species. 

 The group is now divided by Mr. Walker into ten 

 families* (Culicidae and Tipulidae being two of them) ; but 

 even so the Blood-suckers are not entirely separated from 

 the Vegetarians, one genus in Culicidse itself not being 

 blood-sucking, while Blood-suckers and Vegetarians are 

 mixed in other families. 



Indeed, this habit is not so important a difference as 

 we (from an interested point of view) might be inclined 

 to consider it ; for it is evident that of the myriads of 

 Gnats and Midges which are produced in uninhabited 

 swamps and forests, the greater part must die without 

 having ever tasted blood, but having fed, if indeed food 

 is necessary during their short lives, on the juices of 

 plants, which their piercing and sucking probosces are 

 as well suited to obtain as the fluids contained in the 

 veins of animals. The pupa3 in Nemocera are naked. 



* Mr. Walker, indeed, reckons eleven families in Diptera, the Flea* 

 forming one of these ; but in the present work these form an order by 

 themselves. 



