Katydid \Ka"ty*did`\, n. (Zool.)
A large, green, arboreal, orthopterous insect ({Cyrtophyllus
concavus}) of the family {Locustid[ae]}, common in the United
States. The males have stridulating organs at the bases of
the front wings. During the summer and autumn, in the
evening, the males make a peculiar, loud, shrill sound,
resembling the combination Katy-did, whence the name.
[1913 Webster]