What evocalis is incorrectly written and should be written as "evocatis" as meaning:
They probably wanted to say " 34 evocatis;. If so, it would be a Latin word in dative or ablative plural of the participle evocatus - to - verb 34 um; I recall " which means call, do come. In the works of Julio César usually appear frequently formmando part of a clause which is called absolute ablative.
