When there is more than one available name potentially applying to a taxon, which one of these should be used as valid is determined in part by the past usage of these names.
Eurhynchides Billberg 1828, Microglossidae Hogg 1846 and Proboscigeridae Mathews 1916 are all available names, formed from genus-group names that are synonymous.
The first of these, Eurhynchides Billberg 1828, is invalid because the name of its type genus was suppressed in Opinion 1352
v.42:pt.1-4 (1985:Apr.-Dec.) - The Bulletin of zoological nomenclature - Biodiversity Heritage Library (see
Art. 39).
Microglossidae is (much) older than Proboscigeridae but, as
Microglossus is in the synonymy of
Probosciger and Proboscigeridae 'replaced' Microglossidae before 1961, Art.
40.2 of the Code protects the younger synonym, by giving it the precedence of the older synonym,
if it is in prevailing usage.
In other words : the Code is asking us to go through all the most recent (
published !) works where one of these two names was used, and count how many authors used one or the other; if "at least a substantial majority" of the authors used a name based on
Probosciger, then (assuming a tribe -- you make it a subfamily) Proboscigerini Mathews 1916 (1846) should be used; in the opposite case, then Microglossini Hogg 1846 should be used.
Joseph et al, in 2012, did not regard Proboscigerini as having reached prevailing usage and recommended using the older synonym, Microglossini. Gregory & Sangster now disagree and recommend using Proboscigerini instead. This was in part a result of you having used this name in your book.