INSECT MUSICIANS SNODGRASS 



415 



The musical instruments of the katydids are quite different from 

 those of the grasshoppers, being situated on the overlapping bases of 

 the front wings or tegmina. On this account the front wings of 

 the males are always different from those of the females, the latter 

 retaining the usual or primitive structure. The right wing of a 

 female of one of the more grasshopperlike species, Orchelimum 

 laticauda (fig. 16), is shown 

 at C of Figure 5. The wing 

 is traversed by four prin- 

 cipal veins springing from 

 the base. The one nearest 

 the inner edge is called the 

 cubitus (Cu) and the space 

 between it and this margin 

 of the wing is filled with 

 a network of small veins 

 having no particular ar- 

 rangement. In the wings 

 of the male, however, 

 shown at A of the same 

 figure, this inner basal field 

 is much enlarged and con- 

 sists of a thin, crisp mem- 

 brane (Tm), braced by a 

 number of veins branching 

 from the cubitus (Cu). 

 One of these (fv) , running 

 crosswise through the mem- 

 brane, is very thick on the 

 left wing, and when the 

 wing is turned over (B) it 

 is seen to have a close series 

 of small cross ridges on its 

 under surface which con- 

 vert it into a veritable file 

 (/). On the right wing 

 this same vein is much 

 more slender and its file is very weak, but on the basal angle of 

 this wing there is a stiff ridge (s) not developed on the other. The 

 katydids always fold the wings with the left overlapping the right, 

 and in this position the file of the former lies above the ridge 

 (s) of the latter. If now the wings are moved sideways, the file 

 grating on the ridge or scraper causes a rasping sound, and this is 

 the way the katydid makes the notes of its music. The tone and 



Fig. 5.— The front wings or tegmina of a meadow 

 grasshopper {Orchelimum laticauda),, illustrat- 

 ing the sound-making organs typical of the katy- 

 did family. A, left front wing and hasal part 

 of right wing of male, showing the four main 

 veins, subcosta (8c), radius (R), media (M), and 

 cubitus (Cu), also the enlarged basal, vibrating 

 area or tympanum (Tm) of each wing, the thick 

 file vein (ft;) on the left, and the scraper (s) on 

 the right. B, lower surface of base of left wing 

 of male, showing the file (f) on under side of the 

 file vein (A, fv). C, right front wing of female, 

 which has no sound-making organs, showing sim- 

 ple, normal venation. 



