[Meta menardi]

When sticky silk is spun, it is evenly covered with ...sticky, but this separates into globules, and I think these are the basis for your dew drops.

A very speculative punt, but lozenge shaped cells in the web are sometimes found in Nuctenea umbratica webs, that is usually a large robust web. Tetragnatha webs are usually almost horizontal, very fine and have an open centre and less regular rhomboid shaped cells, so you pays your money and yer takes yer choice. As I say, very speculative.