COLLECTING DIPTERA. 243 



silent and rapid ; some species frequent sandy places. Chiefly 

 from the south coast. Not unconnnon. 



Leptid.e : about 12 species. — Frequenting hedges, woods, 

 thickets. The larv£B are found in the earth in sand or decayed 

 wood ; tl)e larva of one species is aquatic. Some species inhabit 

 marshes and ditches. 



Empid.e : about 180 species. — Found in ditches, fields, moors, 

 woods, and on the banks of streams. Mostly carnivorous. Many 

 species swarm on fine evenings over streams. Some species 

 inhabit dry herbage, running with great swiltness over the leaves ; 

 some on hotbeds ; a few on the sea-coast. Mostly common. 



DoLiCHOPODiD.E : about 160 spccies. — Predaceous. Running 

 on the surface of ponds with great ease. Mostly carnivorous. 

 Some frequent dry shady places, congregating in small troops. 

 Several genera comprise very minute brilliantly-coloured species. 

 Some species inhabit the sea-coast, and a few appear only in hot 

 sunshine. Mostly common, nearly' all the species being brightly 

 coloured. 



Syrphid.e : about 210 species. — Brilliantly-coloured flies, 

 very connnon, many resembling bees and wasps ; flight swift, 

 with a shrill hum, the flies hovering in the air motionless above 

 a flower, and darting in any direction with great swiftness, 

 usually returning again and again to the same spot. Tiie larvse 

 live in stagnant water, decomposing matter, mud, &c. The perfect 

 insects suck the juices of flowers. Occasional swarms of Syrphida3 

 Lave been recorded, in which several species often take part. 



CoNOPJDiE: 17 species. — Frequent flowers, the larvae being 

 parasitic on bees. Chiefly from the south coast. All the species 

 are more or less rare, many resembling wasps, from the contracted 

 first abdominal segment. Some are taken on sandy banks. I am 

 working up all the European species of this family, and any 

 correspondence on this group would be especially agreeable. 



QlisTRiD.i: : species. — Parasitic on horses, sheep, oxen, and 

 deer. All difiicult to obtain from the rapidity of their flight, and 

 the imi^ossibility of breeding them. If the larva is removed from 

 the animal on which it is living, it is certain to die. The larva 

 takes about eight months to attain its full development. 



MusciD.E : about 950 species. — Nearly half the known 

 European species of Diptera fall in this family, and it will bo 

 advisable to notice each subfamily successively. 



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