Numidiae:Numidia
was the kingdom of Jugurtha and the battlefield for the entire Jugurthine War.
capto Jugurtha:
Ablative absolute. Translated literally as "with Jugurtha having been captured."
AblAbs
per ... Sullam:
Eutropius tends to use per plus an accusative to express who
is causing the action, which, in this case, is the capturing of Jugurtha.
quaestorem:
Quaestors had various functions in Roman government from managing financial matters in the city of Rome to the function here of Sulla:
serving as an aide to a general on campaign or a governor in a province.
ingentem virum:
Though typically translated as "huge" or "immense," ingentem here is referring
not to the physical size of Sulla but rather his "mighty" or "remarkable" nature.
tradente Boccho Jugurtham:
Similar to how Jugurtha originally swayed Bocchus to become his ally,
L. Cornelius Sulla made an agreement with Bocchus that,
if he handed over Jugurtha, Bocchus would receive part of the Numidian kingdom.
AblAbs
qui ... pugnaverat:qui refers back to Bocchus whereas
eo refers to Jugurtha. Before translating, compare the sentence Bocchus pro Jugurtha ante pugnaverat.