122 MITES AND TICKS. 



" The animal itself, on account of its minute size, is seldom 

 seen, and the uninitiated, when first ti'oubled with it, are often 

 alarmed at the symptoms and at a loss to account for them. 

 Fortunately these little plagues never attach themselves to per- 

 sons in such immense numbers as do sometimes young or so- 

 called 'seed' ticks ; but I have known cases where, from the 

 irritation and consequent scratching, the flesh had the appear- 

 ance of being covered with ulcers ; and in some localities, 

 where these pests most abound, sulphur is often sprinkled dur- 

 ing 'jigger' season in the boots or shoes as a protection. 



"Sulphur ointment is the best remedy against the effects of 



either of these mites, though when that cannot be obtained, 



saleratus water and salt water will partially allay the irritation. 



"The normal food of either must, apparently, consist of the 



juices of plants, and the love of blood proves ruinous to those 



individuals who get a chance to indulge it. For 



unlike the true Jigger, the female of which 



deposits eggs in the wound she makes, these 



Harvest-mites have no object of the kind, and 



when not killed by the hands of those they 



torment, they soon die victims to their san- 



guinarj' appetite." 



Another Leptus-like form is the parasite of 



146. Astoma of the the fly, described by Mr. Riley under the name 



^" of Astoma? muscarum (Fig. 14G). How nearly 



allied it is to the European Astoma parasiticum we have not the 



means of judging. 



The European Tetranychus telarius Linn., or web-making* 

 mite, spins large webs on the leaves gf the linden ti-ee. Then 

 succeed in the natural order the water mites (Hydrachua), which 

 may be seeu running over submerged sticks and on plants, 

 mostly in fresh water, and rarely on the borders of the sea. 

 The young after leaving the egg differ remarkably from the 

 adults, so as to have been referred to a distinct genus (Achly- 

 sia) by the great French naturalist, Audouin. They live as 

 parasites on various water insects, such as Dytiscus, Nepa and 

 Hydrometra, and when mature live free in the water, though 

 Von Baer observed an adult Hydrachna concharum living para- 

 sltically on the gills of the fresh-water mussel, Anodon. The 

 species are of minute size. Collectors of beetles often meet 

 with a species of Uropoda attached firmly to their specimens of 



