G30 DIPTERA. 



produced in a summer. A few small fish kept in a cistern or 

 open water cask, destroy the larvae of the gnats as fast as they 

 hatch, and prove a sure defence against these annoying insects, 

 so far as this source is concerned. 



In warm climates, these insects are a serious trouble ; it there 

 becomes indispensable to protect beds against them at night by a 

 netting of gauze, called a Musquito-bar. 



2. Tipulida, (Lat. tipula, a water-spinner,) known asthe DADDY- 

 LONG-LEGS. These, in their slender body and feet, considerably 

 resemble the gnats. Their antennae have, usually, from fourteen 

 to sixteen articulations. Among them are found the insects 

 which do the most serious injury to the crops of the farmer. 

 These are represented in the genus Cecidomyia, including the 

 HESSIAN-FLY, C. destructor, (Lat. destroyer;) the WHEAT-FLY, 

 the pest of wheat-fields, C. tritici, (Lat of wheat;) the WILLOW- 

 FLY, C. salicis, (Lat. of a willow,) found in a reddish gall upon 

 low willow-bushes. 



The WHEAT MIDGE PARASITE, Pfatygaster, (Gr. broad- 

 belly,) tipulce, (Lat. of the tipula,) a minute fly, somewhat re- 

 sembling the Winged Ant, performs the part of a public bene- 

 factor, by depositing its eggs in the larvae of the Wheat-midge, 

 (a single egg in each,) and thus preventing the development of 

 great multitudes of them in the perfect form, though, like some 

 other benefactors, it has been charged with committing the very 

 injuries which it has instrumentally limited. There have been 

 collected in Europe twenty thousand species of insects preying 

 on wheat. 



3. Muscida, (Lat. musca, a fly.) This is a well known and 

 numerous family, as may be inferred from the fact that not much 

 short of eighteen hundred species are described as existing in 

 Europe alone, which is probably not half the entire number. 

 Meigen, a German, described six hundred species which he col- 

 lected in a distance of ten miles circumference. The type of 

 the family, is the common House-fly, Musca domestica,) but 

 great diversity is exhibited in the habits of different species. 

 Among the various kinds, are the FLESH-FLIES, Sarcophagy 

 (Gr. flesh-feeding;) the CHEESE-FLIES, Prophila, (Gr. very fond.) 

 casei, (Lat. of cheese,) the larvae of which skippers infest 

 cheese ; and the species, P. petasionis, (Lat. of gammon.) are 

 found in smoked hams. 



PLAGUE-FLY. During the prevalence of the Yellow Fever in 

 Norfolk, Va., not very long since, the PLAGUE-FLY, as it is called, 

 made its appearance there in large numbers. This is a flat in- 

 sect, with black back and red belly, and has very large wings. 



