THE AIR SAC MITE OF THE FOWL. 
lo 
firmly attached to each other during copulation, so that we 
have failed to observe the copulatory process. 
These observations, in connection with the anatomical char¬ 
acters of the parasite, fully support Megnin in his opinion that 
prior observers had erred in attributing to the mites serious 
mechanical irritations, though failing, in our judgment, to war¬ 
rant him in concluding that they do not cause serious and fatal 
disease. It is evident that in their usual habitat and with their 
anatomical structure their sustenance must be derived from the 
liquids secreted by the membrane upon which they congregate 
and sucked up by the aid of their tubular mouth parts. 
The parasite seems peculiarly erratic in its appearance under 
the microscope, so that the details given by no two authors con¬ 
sulted fully agree with each other nor with those here given. Ger- 
lach figures and describes an acarus wholly nude, both in body and 
legs, while Railliet (Neumann’s Parasites of Domestic Animals, pp. 
243-4) figures a nude body, but with the two anterior pairs of legs 
bearing small, almost transverse, hair-like elevations, in length 
almost as great as the thickness of the leg. Megnin adds sev¬ 
eral hair-like projections emanating from little elevations on 
both the dorsal and ventral sides of the body, figures the same 
hair-like projections on the two anterior pairs of .legs noted by 
Railliet, and adds to the second pair of legs, at the middle of 
the last joint, a large spur pointing backwards, two-thirds as 
long as the ambulacrum and almost as thick, while Z'urn, in his 
Diseases of Poultry,” p. 62, figures the bristles on the body, 
omits those on the extremity except that in the place of the 
prominent spur figured by Megnin he figures a tapering bristle 
almost double the length of that spur. It is not at present 
possible to fully explain these discrepancies in figures and de¬ 
scriptions. They do agree sufficiently in all essential particulars 
to make it evident that each had to do with the same parasite. 
Although we assume that in passing from one fowl to 
another the parasite must for a time live outside the body, its 
discovery in a free state has not been recorded. Reft in the 
body of a dead fowl in a room at a temperature of 70° P^., it 
