Page:Insects - Their Ways and Means of Living.djvu/69

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THE GRASSHOPPER'S COUSINS

plicated sensory receptive apparatus (B) connected by a nerve through the basal part of the leg with the central nervous system.

There are several groups of katydids, classed as subfamilies.

Fig. 20. The probable auditory organ of the front leg of Decticus, a member of the katydid family. (Simplified from Schwabe)

A, cross-section of the leg through the auditory organ, showing the ear slits (e, e) leading into the large ear cavities (E, E) with the tympana (Tm, Tm) on their inner faces. Between the tympana are two tracheae (Tra, Tra) dividing the leg cavity into an upper and a lower channel (BC, BC). The sensory apparatus forms a crest on the outer surface of the inner trachea, each element consisting of a cap cell (CCl), an enveloping cell (ECl) containing a sense rod (Sco), and a sense cell (SCl). Ct, the thick cuticula forming the hard wall of the leg

B, surface view of the sensory organ, showing the elements graded in size from above downward. The sense cells (SCl) are attached to the nerve (Nv) along the inner side of the leg

families. A subfamily name ends in inae to distinguish it from a family name, which, after the Latin fashion, terminates in idae.

THE ROUND-HEADED KATYDIDS

The members of this first group of the katydid family are characterized by having large wings and a smooth

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