118 



MITES AND TICKS. 



I have had the good fortune to observe the different stages 

 of a bird mite, intermediate in its form between the Acarus and 

 Sarcoptes, or Itch mite. On March 6th, Mr. C. Cooke called my 

 attention to certain little mites whicli were situated on the nar- 

 row groove between the main stem of the barb and the outer 

 edge of the barbules of the feathers of the Downy Woodr 

 pecker, and subsequently we found the other forms in the down 

 under the feathers. These long worm-like mites were evidently 

 the young of a singular Sarcoptes-like mite, as they were found 

 on the same specimen of Woodpecker at about the same date, 

 and it is known that the growth of mites is rapid, the metamor- 

 phoses, judging by the information which we now possess, occu- 

 pying usually but a few days. 



The young (though th.ere is, probably, a still earlier hexapo- 

 dous stage) of this Sarcoptid has an elongated, oblong, flattened 

 body, with four short legs, provided with 

 a few bristle-like hairs, and ending in a 

 stalked sucker, by aid of which the mite 

 is enabled to walk over smooth, hard 

 surfaces. The body is square at the 

 end, with a slight median indentation, 

 and four long bristles of equal length. 

 They remained motionless in the groove 

 on the barb of the feather, and when 

 removed seemed very inert and sluggish. 

 A succeeding stage of this mite, which 

 may be called the pupal, is considerably smaller than the larva 

 and looks somewhat like the adult, the body having become 

 sliorter and broader. The adult is a most singular form, its 

 body being rudely ovate, with the head sunken between the 

 fore legs, which are considerably smaller than the second pair, 

 while the third pair are twice as large as the second pair, and 

 directed backwards, and the fourth pair arc very small, not 

 reaching the extremity of the body, which is deeply cleft and 

 supports four long bristles on each side of the cleft, while other 

 bristles are attached to the legs and body, giving the creature, 

 originally ill-shapen, a haggard, nnkempt appearance. The two 

 stigmata or breathing pores open near the cleft in the end of 

 the body, and the external opening of the oviduct is situated 

 between the largest and third pair of legs. No males were 

 observed. In a species of Acar\is (Tyroglyphus), somewhat 



143. Esg-eating Mite. 



