The Collector shall fix a day for hearing the appeal, and shall cause notice of the same to be served on the respondent in the manner hereinbefore prescribed for the service of summons. If, no the day fixed for hearing the appeal or any other day to which the hearing may be adjourned, the appellant shall not appear in person or by an agent, the appeal shall be dismissed for default. If the appellant shall appear and the respondent shall not appear in person or by an agent the appeal shall be heard ex parte.