ANTRNN.K. 



2 7 



may be reduced to the merest vestiges even in flies which 

 are more or less predaceous in habit and which have the 

 mouth-parts, with the exception of the mandibles, other- 

 wise well developed ; they may indeed be absent or pres- 

 ent in otherwise closely related genera of flies. They are 

 seldom much elongated, save among some of the Nemo- 

 cera. 



ANTENNAE. 



Fig. 5. Antennae. 1, Tipulidse {Polymera, female); 2, Tipulidse 

 (Rhipidia, male); 3. Culicidte (Aedes, male); 4, Tabanidse (Stibaso- 

 wa)\ 5, Kmpididae {Orapetis); 6, Syrphidae ( Volucella); 7, Tachinidae 

 ( Gonia). 



No other organs furnish so many or so important char- 

 -acters in the classification of Diptera as do the antennse, 

 or feelers as they are sometimes called. The number, 

 shape and arrangement of the joints or segments offer 

 not only the best of specific characters in nearly all cases, 

 but also not rarely generic, family and even subordinal 

 characters. Only in very exceptional instances is the 

 number less than three, and it is probable that, even 



