given there are after removing a few spurious objects and globular clusters (listed in Table \[tab:spurious\]).

After cross-identifications, we ended up with a final sample of 3904 stellar clusters, of which 2247 are *optical*, 1493 *NIR*, and 164 *MIR* clusters. Taking into account the repetitions within each category, but not between them, the numbers of objects are 2247 for *optical*, 1950 for *NIR*, and 197 for *MIR*. Note that the low number of *MIR* clusters is due to the confined Galactic range of the GLIMPSE survey; actually, when only considering the ATLASGAL range, which is similar to the GLIMPSE range, the numbers of objects are of the same order for the different categories: 227 *optical*, 315 *NIR*, and 153 *MIR* clusters, after merging.

As argued in Section \[sec:spurious\], for ECs (as defined in this work) we expect a minimal contamination by spurious detections, whereas for OCs that have not been confirmed by follow-up studies, we estimate a spurious contamination rate of $\sim 50\%$, following @Froebrich2007.

New search for ECs in GLIMPSE {#sec:newglimpse}
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The GLIMPSE on-line viewer[^4] from the Space Science Institute represents a very useful tool to quickly examine color images constructed from data collected in the four 3.6, 