l886.] NEW-YORK MICROSCOPICAL SOCIETY. 35 



OBJECTS EXHIBITED. 



1. Diatoms mounted in Prof. H. L. Smith's new Medium : by 

 C. Van Brunt. 



2. Sections of Echinus Spines {Diadema setacea) : by J. D. 

 Hyatt. 



3. Dichroism of certain New-York Micas : by J. D. Hyatt. 



4. Section of Lava from Nevada : by J. D. Hyatt. 



5. Amber, enclosing various Diptera : by Wm. G. De Witt. 



6. Achenia of Cyperus JIavescens, L., and C. diandrus, Torr. : 

 by N. L. Britton. 



7. Sarcoptes scabiei (Itch Mite), male and female : by C. S. 

 Shultz. 



8. Mycelium, Pileus, and Spores of Lentinus lepideus, Fries : 

 by P. H. Dudley. 



THE ITCH MITE. 



Mr. Chas. S. Shultz exhibited a slide containing specimens of 

 one of the Acari, Sarcoptes scabiei {lich. Mite), the cause of Sca- 

 bies or " Itch," a parasitic disease of the human skin, and said: — 



" This slide contains a mature male and female, an undevel- 

 oped young mite, and an egg. Few only of the younger people 

 in this country have seen cases of Itch, or the mite which causes 

 the disease, although not many years ago the Itch was quite com- 

 mon here. At present, it is prevalent among the peasantry of 

 Central Europe, especially in portions of the Austrian provinces 

 of Hungary, Bohemia, &c., where the people saturate their under- 

 clothing and mittens with grease to protect themselves from the 

 cold, and retain these garments unchanged upon their persons 

 for months. On the warmer parts of the body, especially the 

 arm pits, bends of the elbows, and between the roots of the 

 fingers, the female mite, which is the chief cause of the disease, 

 burrows into the flesh, there depositing her eggs, and, while 

 awaiting their hatching, cuts into the flesh, causing irritating 

 pustules to form upon its surface. When the eggs are hatched, 

 the young Acari rapidly develop, and leave the breeding place, 

 the females starting new burrows or galleries, the males hiding 

 quietly under the cuticle, causing no irritation. The male mite 

 is but one-half the size of the female. The mature Sarcoptes has 

 eight legs. The young begin with six only, but develop the other 

 two after commencing their burrowing. ' The four anterior legs 



