Pennsylvania Code
Title 231 - RULES OF CIVIL PROCEDURE
Part I - GENERAL
Chapter 1700 - CLASS ACTIONS
Appendix A - ANALYSIS OF THE RULES
Rule 1706 - Form of the Answer

In all class actions, including actions in trespass, all the averments of fact under the "class action allegations" will be deemed admitted unless specifically denied in conformity with Rule 1029. The special defense pleading rules in trespass will apply to all the substantive provisions of the complaint, but will not apply to the class action allegations. They must always be answered or they will be admitted.

Contrary to the Federal rule, a general denial is insufficient, nor is a denial sufficient if made in "haec verba". The assumpsit form of specific denial is required.