THE SHEEP-TICK. 633 



The Louse (fig. 290, No. 1). Whenever wretchedness, 

 disease, and hunger seize upon mankind, this horrid 

 parasite seldom fails to appear in the train of such 

 calamities, and to increase in proportion as neglect of 



Fig. ilSS. Malophagus ovinus, Sheep-tick. (The small circl') encloses one 

 of life size.) 



personal cleanliness engenders loathsome disease. When 

 examined under the microscope, our disgust of it is in no 

 way diminished. In the head may he distinguished two 

 large eyes, and near to them are the two antenna ; the 

 front of the head is long, and somewhat tapering off to 

 form a snout, which serves as a sheath to the proboscis 

 and the instrument of torture with which it pierces the 

 flesh and draws the blood. To the fore part of its body 

 six legs arc affixed, having each five joints, terminated 

 by two unequal hooks ; these, with other portions, are 

 covered with short hairs. Around the outer margin of 



