262 The Orders of Insects 



Sub-Order C. Cyclorrhapha. 



The Cyclorrhapha are those Diptera whose larvae 

 are, for the most part, degraded maggots with no dis- 

 tinct head-capsule, the front end of the body being 

 armed with hook-like jaws and capable of protrusion 

 or withdrawal. The pupa is enclosed in the dried 

 larval skin which hardens into an egg-shaped pu- 

 parium ; this opens by the splitting-off of a circular 

 lid at the head end, and allows the developed imago 

 to escape. The flies have short, three-segmented 

 feelers ; the third segment is far the largest and 

 bears a long bristle (fig. 146 c), and (except among 

 the Platypezidae) this bristle springs from the upper 

 edge of the segment. (In some of the Conopidae, 

 see below, p. 263, the third antennal segment bears 

 a terminal claw.) (150, I5I«) 



Platypezidae. — The PlatijpeziJce are a small family of little flies, 

 mostly black in colour, which are distinguished from all the rest of 

 the Cyclorrhapha (except a few of the Conopidx) by having the 

 antennal bristle at the tip of the third segment. From the earlier 

 families in the brachycerous division of the Orthorrhapha the Platy- 

 pezidse may be distinguished by the unforked ulnar nervure. Their 

 rounded wings separate them readily from the Lonchopteridse, and the 

 presence of rounded lobes, marked off from the wing area near the 

 base, from the Empida; and Dolichopida;. The hind-feet are usually 

 very broad ; this also serves as a distinction. Some larvjE of the 

 family are known to live in fungi ; they have a small but distinct 

 head, and paired air-openings on the first and last body-segments. 



Pipunculidse. — The PipuncuUJa are a small family of flies char- 

 acterised by a roundly conical head which is broader than the thorax, 

 by a long anal cell (the cell between the fifth and sixth longitudinal 

 nervures) reaching, or almost reaching, the wing margin, and usually 

 by a narrow cylindrical hind-body brightly marked with yellow. 

 The larvse, which resemble in structure those of the last family, live 

 parasitically on other insects. 



Syrphidae. — The Si/rph'uhe or Hovering-flies are a very large and 

 important family, readily distinguished from all other Diptera by the 

 presence of a slender additional longitudinal nervure {■vena spuria) 

 between the third and fourth. They agree with the Pipunculids in 

 having a long anal cell, and in being usually brightly variegated with 

 yellow on the hind-body. Many of them, especially some of the 



