“Frog-Spit,” or “Froth-Spit.” The spume which forms the uidus of an insect called the Cicada Spumaria, or, more strictly speaking, the Cercopis Spumaria (one of the three divisions of the Cicadariæ). This spume is found on lavender-bushes, rosemary, fly-catch, and some other plants. Like the cochineal, the cicada spumaria exudes a foam for its own warmth, and for protection during its transition state. The word “cuckoo” in this case means spring or cuckoo-time.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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