THE STKIDULATION OF COEIXA [RHYNCHOTA] . 

 By G. W. Kirkaldy, F.E.S. 



In the * Irish Naturalist,' 1894, pp. 253-6, G. H. Carpenter 

 discussed this interesting subject, and concluded that it was 

 caused by the movement of the " comb " on the inner surface of 

 the anterior tarsi across the face. Corixa does at times move the 

 anterior tarsi across the face, but this, I believe, is merely to 

 cleanse the latter (and possibly the former). The stridulatory 

 area lies, in fact, on the inner surface of the anterior femora, 

 close to the base. It consists of a very large number of minute 

 sharp points, arranged regularly in more or less parallel rows. 

 The stridulation is caused by one of the tarsi being drawn across 

 the femur of the opposite leg. For stridulation to take place 

 through the interaction of the tarsus and the face, the movement 

 would have to be longitudinal (whereas it is actually transverse), 

 the apical part of the face being strongly multicarinate trans- 

 versely.* 



This femoral area and the tarsal comb are not found in any 

 females of Corixa, aud not in the males of Cymatia, Flor, usually 

 treated as a subgenus of Corixa. It therefore seems well to treat 

 Cymatia as a distinct genus, as was done by Douglas and Scott. 

 The whole apparatus can be seen very clearly in C. geofroyi, 

 Leach, from which the accompanying figures are taken. 



.^ 



1 s 



Explanation of Figures. 



Fig. 1. Anterior femur, tibia, and tarsus of C. geoffroyi. a, femur; 

 6, stridulating area; c, tibia; d, tarsus; e, "comb"; fandg, two rows of 

 bristly hairs. 2. Femur further enlarged. 3. Tarsus further enlarged. 

 Letters as in fig. 1. (The two rows of bristles are not shown in fig. 3, and 

 the figures are all a little diagrammatic for the sake of clearness.) 



* It is true that this part of the face is also medianly carinate longitudi- 

 nally, but it could scarcely be a stridulatory area adapted to the highly 

 specialised tarsal apparatus, and moreover this form of the face is common 

 to both sexes. 



