FLIES. 221 



insect. A South American species (Paltostoma Torrentium of F. 

 Miiller) exhibits a very peculiar form of female dimorphism. The 

 male lives on flowers, like that of other gnats, and one of the 

 female forms is adapted to a similar life, while the other is fur- 

 nished with a lancet-like arrangement like that of the female gnats, 

 and sucks the blood of animals. 



Family VII. — CuUcidce. 



Head small ; eyes round or kidney-shaped ; ocelli wanting ; 

 antennae long, fifteen-jointed, pectinated in the male ; abdomen, 

 wings, and legs, all long and slender ; larva often aquatic. 



This family contains the small delicate dull-coloured insects 

 too well known in all parts of the world as gnats and mosquitoes. 

 They are most abundant in the neighbourhood of water ; for the 

 female constructs a sort of raft of her eggs, which floats on the 

 surface. When the larva is hatched, it floats tail upwards, being 

 provided with respiratory organs at the extremity of its body, and 

 rises occasionally to the surface to breathe. The pupa, however, 

 which is of a somewhat conical shape, floats with its head 

 upwards. 



Family V III. — ChironomMce. 



Head small, retracted, often partly covered by the thorax; 

 eyes generally kidney-shaped or crescent-shaped ; ocelli absent or 

 rudimentary ; antennae with from six to fifteen joints, densely 

 pectinated in the males, and simple, and often composed of fewer 

 joints, in the females ; abdomen and legs long and slender. 



The CJiironomidce are small delicate insects, much resembling 

 the gnats. The females of several species are bloodsuckers. The 

 larvse of some species are aquatic, and those of others live under 

 bark, in dung, or among decaying vegetable matter. The larva of 

 Chironoiims Plumosus, Linn., which is common in stagnant water, 

 is called the Bloodworm, from its bright red colour. The larvse 

 of several species are actually marine, feeding on seaweed, etc., at 

 low water. Clunio Marimcs, Hal., is far from uncommon on our 

 British coasts, and Chironomus Oceanicus, Packard, has been met 

 with by that author in Salem Harbour. 



Family IX. — OrphnepJdlidce. 



Head small, round ; eyes round, contiguous in front ; ocelli 

 absent ; antennae shorter than the palpi, placed near the mouth ; 



