230 DIPTEKA. 



very rapid in their movements. The family is extensive, including 

 a considerable number of genera and species. 



FAMILY XXIX. Lonchopteridce. 



Head egg-shaped, as broad as the thorax ; first two joints of 

 the antennae very small, setaceous, the third rounded, finely pubes- 

 cent, with a slender terminal bristle ; eyes prominent, green in life ; 

 ocelli present ; abdomen long, narrow, and compressed ; legs long, 

 with slender spines. Metamorphoses unknown. 



The species of Lonchoptera, Meig., are small, yellow, brown, or 

 greenish flies, with lanceolate wings, which frequent the banks of 

 shady streams, and are often found resting on the wet stones. 



FAMILY XKK.Syrphidce. 



Head semicircular, as broad as the thorax ; antennae close 

 together at the base, third joint variously formed, but generally 

 somewhat compressed, with a tuft on the back ; eyes rather large, 

 generally contiguous in the males ; ocelli present ; legs and abdo- 

 men various in structure ; habits, both of larvae and perfect insects, 

 very various. 



The Syrphidce are moderate-sized flies, often of brilliant colours, 

 many being very common. Except the enormous family of the 

 Muscidce, the present is one of the largest families of the Diptera 

 Bmchycera. Many of the species may be recognised at once as 

 belonging to the Syrphidce by their mode of flight alone, for they 

 hover motionless in the air, and, if alarmed, dart off with a rapid 

 motion that the eye cannot follow, and hover again as soon as they 

 stay their course. It is no easy matter to capture the larger species 

 on the wing. 



The species of Syrphus, Fabr., are black or metallic green 

 species, with a rather long abdomen, marked with yellow bands, 

 often interrupted in the middle ; the larvae feed on Aphidce. The 

 flies are about half an inch long, and are common in gardens. 



Several of the largest and handsomest species of European Syr- 

 phidce belong to the genus Volucella, Geoffr. They are sometimes 

 found on leaves and flowers, and at other times may be seen sus- 

 pended in the air in the glades of woods. The flies themselves are 

 more robust, and usually more hairy than the species of Syrphus, 

 though some few, like the latter, are nearly naked. The larvae are 

 parasitic in the nests of wasps and humble-bees. The flies vary 



