396 DIPTERA. 



running into tlie border of the wing, wtiile the anterior tibiae 

 end in a hooked spine. 



The genus Laphria is large, stout-bodied, very hirsute, the 

 second longitudinal vein runs into the first, and the stjde of 

 the antennae is either tliick and stout, and generall}^ wanting, or 

 entirely obsolete. In their loud buzz, swift, peculiar flight and 

 general appearance, the species strikingly resemble humble 

 bees. Lcqyhria tJioracica Fabr. is nearly an inch long, and is 

 black with yellow hairs on the thorax. Asilus is much longer, 

 with an acutely pointed prolonged abdomen, and the species are 

 often nearl}^ naked, while the more essential characters lie in 

 the union of the second longitudinal vein with the first, and the 

 termination of the antennte in a distinct bristle. The larvoe 

 of Asilus sericeus Say, Avhich feed on roots of the rhubarb 

 plant, according to Dr. Harris, are yellowish white, about 

 three-quarters of an inch long, a little flattened and tapering 

 at each end, with a small brown, retractile head, which is pro- 

 vided with two little horny brown hooks. The brown pupa is 

 naked, with a pair of tubercles on the front of the head, three 

 spines on the side, a forked tail, and a transverse row of fine 

 teeth across each abdominal segment, by which they are en- 

 abled to work their way to the surface. The Trupanea cqjivora 

 Fitch, or Bee-killer, captures the honey bee on the wing, one 

 having been known to kill 141 bees in a day. (Eiley.) 



Therevid^e Westwood. This small group is characterized 

 by the wings having the three basal cells much prolonged ; the 

 third longitudinal vein is furcate, and the antennae have a ter- 

 minal st3de of variable form, sometimes wanting. There is no 

 em[)odium, and the labium is fleshy. The larva is very long 

 and slender, the abdominal rings having a double segmented 

 appearance, with two respiratory tubes at the end of the body. 

 They are found in garden mould and rotten wood. The pupa is 

 oblong, with two spines on the front of the head, and three on 

 the side of the thorax. \Yestwood states that the larva of a 

 species of Thereva, which is like a wire-worm in shape, feeds 

 on the pupae of some moths. 



BoMBYLiiD^ Latreille. These pretty flies are very hirsute, 



