148 Objects for the Microscope. 



ACARUS PASSERINUS. 



Found on all young birds. 



1XODES, OR DOG-TICK, 



a curious parasite, which has no perceptible eyes. It has 

 a toothed beak, which it fixes in the skin of the dog and of 

 the hedgehog, and it holds so tightly that it can scarcely 

 be detached alive. It deposits a prodigious number of 

 eggs, and are so voracious as to cause the death of some 

 animals from exhaustion. 



MELOPHAGUS. 

 (Sheep-tick.) 



This parasite belongs to the Diptera, though it is wing- 

 less. They abound on sheep, are easily taken and prepared. 

 Let them soak in potash for at least a month, then press 

 them and wash them well ; when dry, soak in turpentine 

 before mounting in balsam, and their structure will be 

 well seen. They are very brilliant objects when viewed 

 with polarized light. 



The Melophagus is one of the family Hippoboscida, of 

 which there are six genera, all of them parasites of mam- 

 malia and birds, feeding on the substance at the roots of 

 the hairs and feathers. The species pass their egg and 

 larva state in the body of the mother, who produces only a 

 single egg at a time, which is in reality a pupa. This 

 pupa egg is nearly as large as its parent, and has a slight 

 motion, with spiracles, or rather spiraculiform points, 

 down each side, and in a short time it changes to a perfect 

 Fly. 



The Melophagus has no wings, but six stout bristly legs 

 with very long curved and toothed claws, which they fix in 

 the wool of the sheep. The head is very large, broader 

 than the thorax ; the antennae are mere tubercles ; the eyes 

 small, oblong, and bare. The mouth consists of a pair of 

 short hairy valves, in which a long sucking-tube is con- 

 cealed ; it usually uncoils in mounting, and is well seen as 

 a very fine hair, protruding from between the valves. 



