BIRD LOUSE MITES. 



329 



CASE Dermaleichus pici majoris {BtickhoJz). From the greater woodpecker. — 

 ^^- 20. Magnified sketch of male; 21. Ditto of female. Copied from 



20, 21. Buckholz's figures. 



No. 22. Dermaleichus chelopus {Herm. ; D. passerinus, JiToc/i). From the 

 sparrow. — 22. Magnified sketch of male. 



Dermaleichus chelopus (male). 



Ditto (female). 



This is very like, although in some respects it slightly differs 

 from, the Acarus passerinus of Koch ; but these discrepancies are 

 probably only differences in maturity, or drawing. 



Genus Incert^ sedis. 



Demodex folliculorum {Simon, Owen, &c.) — 23. Magnified sketch of 

 bulb of a human hair, with the sebaceous follicle attached, in the tube 

 of which a minute speck represents the insect ; 24. Magnified sketch of 

 the insect. 



This minute animal which is from i-5oth to i-iooth of an inch 

 in length, is a parasite that lives in the sebaceous sacs and hair 

 follicles of the human skin. Considerable difference of opinion 

 has existed amongst naturalists as to its proper place in the 

 animal kingdom — but there seems little doubt that it is an Acarid, 

 although the mode of articulation of its thorax is anomalous. 



