SYRPHID^E. 83 



and numerous specimens are sure to appear in any general 

 collection of insects. None are injurious in their habits to 

 man's economy and many are very beneficial. In their adult 

 habits they all show a great uniformity. They are flower- 

 flies and feed upon honey and pollen, loving the bright 

 sunshine. 



The larvae are usually not very elongate, with firm, some- 

 times tough skin, the head-segments small and extensile, the 

 head not distinctly differentiated. The external mouth-parts 

 are either wholly wanting, with only a soft fleshy opening, or 

 there are two or four outwardly directed booklets. Antennae 

 short, small, one or two jointed and fleshy. Body smooth or 

 provided with soft conical projections and bristles ; below 

 usually with seven pairs of abdominal feet. At the posterior 

 end the body terminates in a more or less elongate tube, sin- 

 gle or double, the stigmata. This tube sometimes forms a 

 short, almost chitinized, tubercular projection on the dorsal 

 part of the last segment; at other times it is very long, longer 

 than the body, slender and composed of two joints, the one 

 sliding within the other, like the joints of a telescope. In 

 changing to the pupal condition, the larval skin contracts to 

 form the pupal envelope, and the body becomes shorter, more 

 oval and of a darker color, the elongated respiratory tube, in 

 the "rat-tailed" species, being curved over the back. Unlike 

 all the other Cyclorrhapha, except the Pipunculidse, the fron- 

 tal lunule is not used in springing off the cap to the puparium. 



The habits of the larvae are more variable than those of the 

 adult flies. A large number live in decaying wood, or other 

 vegetation, or in ordure, or decomposing animal remains. 

 Some live in the stems of various plants, some in fungi. The 

 larvae of many species of the Syrphini are aphidophagous, 

 crawling about on the stems of plants frequented by plant- 

 lice and destroying them. Some live in ant's nests and may 

 be parasitic ; others in the nests of humble bees. 



On account of the large number of genera and the conse- 



