372 



ZOOLOGY 



are deposited amongst the dust in cracks or crevices ; the 

 small larvae have distinct head and jaws. 



Pulex irritans is the common flea. Sarcopsylla penetrans is 

 the chigoe or jigger of South America ; the female burrows 

 into the foot of man or other mammals, and deposits her eggs 

 there. If not removed the larvae hatch out and give rise 

 to ulcers. 



Sub-order 2. Diptera genuina. 



Family Culicidae (gnats and mosquitoes). — The members 

 of this family are provided with very long and slender mouth 

 parts. They are very widely distributed, extending from the 

 arctic circle to the equator ; the females lay their eggs on the 

 surface of the water, on which they float in a boat-shaped mass. 

 The larvae live at the bottom of ponds or swamps, eating 

 decaying vegetable matter, and occasionally rising to the sur- 

 face for air, which they take in through a special respiratory 

 tube. The pupae are curiously curved and somewhat club- 

 shaped ; they swim actively about. The males do not leave 

 the neighbourhood of the swamps where they are bred, but the 

 females infest houses, etc. Gulex pipiens is the common species 

 of gnat in Britain. 



Fig. 209. — Tipula oleracea (the daddy- 

 long-legs). 



1. Larva. 



2. Pupa case. 



3. Imago. 



4. Eggs, natural size. 



• Family Tipulidae (daddy-long-legs or crane-flies). — The 

 familiar daddy-long-legs , has long filiform antennae and very 



