402 DIPTEKA. 



carpets, and is remarkable for the double segmented appearance 

 of all the abdominal segments, except the last one, so that the 

 body, exclusive of the head, seems as if twenty -jointed instead 

 of having but twelve joints. The head is conical, one-third 

 longer than broad, and of a reddish brown color, while the 

 body is white. It is .05 of an inch in length. The larva is 

 also said to live in rotten wood, and is too scarce to be destruc- 

 tive to carpets. The fly is 1 thick, with a metallic hue, and 

 with pale feet 



The genus Platypeza also represents the Platypezidce of 

 Meigeu, the antenna? of which have an apical bristle, with the 

 7iiale genital armor (hypopygium) turned symmetrically under 

 the abdomen. The middle tibia? are provided with spurs, and 

 the empodinm is wanting. The larva is flat, with rigid curved 

 bristles along the side. It lives in rotten mushrooms. 



KMPID.K Leach. The species of this family closely resemble 

 the Asilida; in their long body, incumbent wings, and rapaci- 

 ous, carnivorous habits. The flrst joint of the antenna? is not 

 much shortened, and the third joint has an apical or dorsal 

 bristle, while the empodium is usually membranaceous and of a 

 linear form. The head is small, spherical, the eyes united in 

 the male ; the proboscis is horny, without a distinct tongue, 

 and bent vipou the breast. The slender larva?, whose segments 

 are much constricted, arc found in garden mould. The species 

 hover in swarms over standing water, ftying backwards and for- 

 wards as if by a common impulse. They appear very early in 

 the spring, or in autumn. The genera Hybos and Tachydromia 

 represent small groups which are closely allied to Empis. 



E Latreille. Loew has characterized this 

 well marked family as generally comprising metallic green, 

 brisk and restless Diptera of small or medium size, predatory 

 on other insects, and living principally in damp situations ; the 

 larva? living under ground or in decaying wood. The head is 

 hemispherical, the eyes large and hairy, the antenna? are 

 stretched straight out, with a two-jointed bristle. The probos- 

 cis is short and stout, concealed above by the single jointed, 

 usually scale-shaped palpi, with a wide opening which can be 



