336 INSECTS, 



you : little dreaming that the little Fly, and the big Fly, 

 and the Fly which bites you, not only are different species, 

 but even belong to different genera : that the little Fly 

 never grows big, that the big Fly never was little, and 

 that their Housefly could not bite you if he would. 



What, then, are we to understand by the name Fly ? 

 It is clear that the popular sense has no sense at all 

 or too many senses and yet the word cannot be spared 

 from our vocabulary. In any Latin dictionary we shall 

 find Musca (Fly), and the Entomologist pounces upon it, 

 and says, it shall mean the tribe of two-winged insects. 



LinnaBus so used it, and his genus Musca, now broken 

 up into many new genera, represented the greater number 

 of those insects which the Entomologist now claims as 

 Flies. 



The order DIPTERA, then, is marked by the absence 

 of hind-wings, the place of which is occupied by two 

 small, short, hair-like appendages, ending in a knob, 

 and termed halters or poisers. The wings are mem- 

 branous, not closely veined, and are never folded. At 

 their base, a little wing-like membrane, called alulet, 

 or winglet, is most frequently found. 



The mouth is fitted for sucking only, and its principal 

 parts are a sucker, or fleshy tongue, familiar to us as 

 the " proboscis," or " trunk" of the Housefly, and 

 several fine lancet-like organs. It is these latter which, 

 in the blood-sucking Flies, or Gnats, Horseflies, &c., are 

 used to pierce the skin, while the fleshy tongue or sucker 

 makes a vacuum, and draws away the blood. In fact, 

 when a Gnat " bites" us, the truth is, that the little crea- 

 ture puts us through the exact process of cupping. The 

 fleshy sucker is the labium, lip, or tongue, as it is 

 variously called in this and other insects. The lancets 



