ON TRACHEAX ARACHXIDA, 531 



The sexual intercourse of these mites takes place in the 

 same manner as that of other insects. The female lays some 

 oval eggs, very white, and which appear to be reticulated or 

 spotted with brown. 



Leuwenhoek, who has particularly observed this species, saw 

 but six feet upon the little ones just disclosed; and the same 

 has been remarked in relation to the mite of the itch. Pro- 

 pagation goes on even in winter, at least in our houses, the 

 temperature which reigns there being favourable to the activity 

 of these little animals. 



Acai'iisfarince, Deg. (the mite in flour), is elongated, white, 

 with the anterior part reddish, and advanced in the form of a 

 thick and conical muzzle. The eight feet are thick, and 

 tolerably long, especially those of the first two pair. The 

 body also has hairs, and those of the hinder part ai'e very long. 

 Degeer could not perceive at the extremity of the feet the 

 vesicle which we have mentioned belonging to the feet of the 

 preceding species. These animals walk tolerably fast. 



Linnaeus at first distinguished separately the mite of the 

 itch, but he subsequently confounded it with the two preced- 

 ing species. 



"The mites," says Degeer, "which I had occasion to ex- 

 tract from the ulcers of the itch, were very small, and not 

 larger than grains of ordinary sand. The colour of the body 

 is white, and transparent ; but the head and feet have a slight 

 tinge of red or yellowish brown. The body is of a rounded or 

 almost circular figure, and its surface is rugged, having ine- 

 qualities, and here and there some hairs, but in small quanti- 

 ties. The head is in the form of a muzzle, short, cylindrical, 

 rounded at the end, and furnished with some hairs ; but the 

 smallness of the insect prevented me from detecting its parts, 

 and ascertaining their true construction. Not having been 

 able to remark upon the back two curved brown lines of which 

 Linnaeus speaks, I have reason to believe that the mite of vvhicli 



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