SEVENTH ANNUAL REPORT. 129 
TRICHODECTES CERVUS: HAIRLING. 
dom made, since similar remedies are amply adequate when 
thoroughly applied to destroy both alike. 
The particular significance of this outbreak lies in the fact 
that these mites may at any time become epidemic, at least in the 
deer family, while at range, whereas the pediculus or louse is 
seldom or never known to become troublesome outside winter 
quarters, where treatment may be easily and successfully carried 
out. 
The hairling kills from general irritation rather than by reason 
of living upon the blood and lymph of the host, as in the case 
of the louse, being, as may easily be discerned from the accom- 
panying micro-photograph, essentially constructed to fare di- 
rectly upon the epidermal cells and hair structure; hence the 
name hairling. 
