Vol. XXVIII 

 1911 



Ewing, English Sparrow and Bird Mites. 339 



cage. On July 20, 50 individuals of the bird mite, Dermanyssus 

 avium DeGeer, were placed upon the chicken in the cage. These 

 mites were taken from a young robin; plenty of them were also 

 found on sparrows and mourning doves. On the 24th, four days 

 later, a careful examination was made of the chicken, but not a 

 single one of the mites were to be found. The same results were 

 obtained on the 2Sth and again on August 2. On August 11, three 

 weeks after the original inoculation, not a sign of a mite could be 

 found either upon the chicken, or in the cracks of the box, although 

 if the chicken should have been a natural host to the bird mite, 

 every opportunity for the establishment of the species would have 

 been at hand. 



On August 11, the chicken was now inoculated with individuals 

 of Dermanyssus gallince Redi, taken from the sparrow nest. An 

 examination on the 12th and 13th showed the chicken to be covered 

 with the mites, many of which were next to the skin and feeding. 

 The mites continued to feed upon the chicken and multiplied by 

 the hundreds, even thousands. In the cracks of the box and in 

 old knot-holes they could be found sometimes a quarter or half 

 inch deep. During this time the chicken had become greatly 

 annoyed, and at times would be almost constantly busy scratching 

 itself with its bill. It lost weight rapidly, and became very sickly 

 in appearance. 



On August 20 many of these mites were taken from the chicken 

 and used to inoculate an English Sparrow which had been kept 

 in confinement, and was free from Dermanyssus gallince Redi. 

 The mites at once began to annoy and feed upon the sparrow. 

 In fact their attacks became so vigorous that the bird soon suc- 

 cumbed, and upon examination after death, before it had become 

 cold, many individuals were found upon its skin and feeding. 



Having thus established the fact that the mites found in the 

 sparrow's nest could be inoculated upon the chicken, that the same 

 mites after feeding for a long period upon the chicken could again 

 be inoculated upon the sparrow, I made some observations for 

 testing the ability of Dermanyssi to travel when off of a host, and 

 upon the length of time which they could live when entirely with- 

 out food. Many individuals of Dermanyssus avium, were confined 

 in a small glass cell entirely without food. They apparently did 



