366 THE ATHERICERA. 



my readers the trouble of going far to seek for 

 an illustration of this group of Flies, and myself the 

 labour of giving them a detailed description of its 

 appearance. If we examine a specimen of the com- 

 mon House-fly (Musca domesticd) with a view to the 

 discovery of the principal characters in which it differs 

 from the members of the preceding groups, we find 

 that it is most strikingly distinguished from the 

 last tribe by the structure of its antennae. These 

 organs are short and consist of three joints, of which 

 the third is large, oblong, and destitute of any signs 

 of articulation, but furnished with a rather long plu- 

 mose bristle, which springs from its back near the 

 base. From the lower part of the head arises a thick 

 geniculated proboscis, terminated by a pair of large 

 fleshy lobes, and bearing a pair of short palpi on its 

 stalk near the geniculation. In repose this proboscis 

 is capable of being entirely retracted within a cavity 

 in the lower part of the head, and even when it is 

 extended, the palpi are concealed in the same hollow. 

 In these characters of the antennae and proboscis, 

 the whole of the insects belonging to the tribe ATHE- 

 RICERA*, of which the common Fly is so distinguished 

 a member, pretty closely agree; the antennae are 

 always small and composed of three joints f, and the 



* Gr. other, a beard (of corn) ; keras, a horn. 



t The genus Conops furnishes the only exception to this cha- 

 racter. In it the antennae are rather long, prominent, and geni- 

 culated, almost as in Stratiomys, but of a very different con- 

 struction, being composed of three principal joints, of which the 

 second is considerably longer than either of the others, whilst 

 the third, which is of an ovate conic form, bears three little joints 

 and a minute style at its extremity. These flies are found about 

 flowers, and one or two species are tolerably abundant. Their 

 larvae are parasitic in the nests of Humble- Bees. 



