DIPTERA. 



CHARACTERISTICS. 



1. Two membranous wings (when wings are present), 

 usually transparent, and borne by the mesothorax. 



2. Hind wings either reduced to mere knobs, halteres, 

 or halteres accompanied by minute wing-like 

 organs called alulets. 



3. Two compound eyes, either contiguous or separated 

 by the frontal lunule. 



4. Antennae inserted near the top of the head line or 

 midway down the face. 



6. A curious, fleshy proboscis with tongue-like flaps, 

 or a complex modification of the mandibles and the 

 maxillae, making needle-like, piercing stylets. 



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