PYGIDIUM OP A FLEA. 151 



called labrum. The thorax is composed of three segments, 

 and the abdomen of seven segments ; the female has nine ; 

 and both sexes on the last segment have that beautiful 

 breathing apparatus called 



THE PYGIDIUM OF A FLEA. 



This must be mounted separately to be seen well, and 

 it forms an excellent test object. Topping mounts it 

 beautifully. 



There are twenty-five disk-like areolse ; in the centre of 

 each of these is a long hair, and round them a ring of 

 rectangular rays. It must be seen rather than described. 



The legs of the Flea are long and many-jointed, the 

 hind pair having thick muscular thighs, formed for extra- 

 ordinary leaps, and terminated by five tarsi, and two curved 

 and toothed claws. Every part is worthy of observation. 



The coxa, or first joint, is very thick ; the trochanter is 

 very small, the femur long and thick, the tibiae hairy. 



There are many species of fleas, each of them parasitic, 

 on various animals, with some difference in structure. The 

 most curious are the 



Pulex talpa, or Mole-flea, with its rows of spines on the 

 neck. 



Pulex GallincBy or Fowl's flea, which does not leap, but 

 runs swiftly, and has a most tormenting bite, driving hens 

 from their nests, and compelling their masters to keep the 

 hen-house clean. 



Pulex Columba, or Pigeon's flea, very curious. The 

 antennae should be particularly noticed ; the male carries his 

 erect, and the female has hers partly concealed in a furrow 

 near her eyes. The form is beautiful, eight cup-like joints 

 set one within another, and surrounded by a circle of stout 

 bristles. 



Pulex vespertilionis, or Bat's flea, has a row of dark 

 spines just over its proboscis, called its cephalic setse, and 

 a collar of spines, called its proto-thoracic setae. 



Pulex felis, the Cat's flea, which has a prettily spotted 

 head, and in which we can see the spiracles on every 

 segment of the abdomen, and also the pygidium, is one of 



