Try searching "cicada" on YouTube in foreign languages.
Like Zikade, Cvrčci, セミ, Cicale, Цикадовые, Τζιτζίκι, böceği, 蝉
Maybe you'll get better sources like this one:
This recording on Wikipedia is also useful:
Have you looked into condenser microphones? Instead of the dynamic mics, condensers are used for more intimate sound recordings. Additional, the Sanken brand makes some microphones for such needs. "Sanken [makes a mic] called the MO-64, which is capable of recording the heartbeat of a snail."
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