IU\ i\ Chordotonal Organs of Cerambycid Larvce 71 



The cap cell is located distad of the enveloping cell, and 

 connects it with the body wall TFigs. 7 and 8, C. C.)- It contains 

 at its base the distal end of the sense cell, with its scolopale. 

 Structurally, the protoplasm of this cell is of a much denser 

 nature than that of either of the other two cells, but about its 

 proximal portion the protoplasm is not as dense as farther 

 distad. The whole cell is more or less filled with dark staining 

 strands, or fibrils (¥.), which pass in a rather winding condition, 

 somewhat as the strands of a rope, to the distal end, where they 

 unite directly to the cuticula (C. C. A.). This cell is exception- 

 ally long and spindle-shaped and, as Weismann suggested, it 

 seems very capable of vibrating. Near its proximal end is a 

 small elliptical nucleus fC. C. N.), containing dark areas of 

 chromatin. 



The portion of the chordotonal ligament anterior to the 

 enveloping cells, and at the sides of the sense cells, is composed 

 of a substance which Schwabe called the "fibrillar binding 

 substance." CFigs. 7, and 8, B. S.). This structure begins to 

 appear in the region of the proximal part of the enveloping 

 cells, and continues along the sides of the sense cells to the 

 anterior attachment. It contains many nuclei, but in no case 

 were cell boundaries seen. These fibrillar strands with their 

 nuclei finally occupy the entire cord at its anterior portion, and 

 by means of these fibrils the cord is fastened directly to the 

 cuticula, much in the same way as at the posterior end. Schwabe 

 regards this fibrillar binding substance as a continuation of the 

 covering of the nerve. This idea seems quite plausible from the 

 appearance of this substance about the sense cells. However, 

 when one considers the character of the fibrils, the nuclei, and 

 the method of attachment, it may be interpreted as a separate 

 modified hypodermal structure. 



All larvae that were studied possessed eight pairs of these 

 abdominal organs. The ones at the anterior part of the abdomen 

 were one-fourth to one-half a millimeter longer than those in the 

 posterior segments, while the others formed a proportional 

 gradation in between. 



Since the four nerve endings of each cord are so arranged 

 that no two are the same distance from the posterior attach- 

 ment, it seems very evident that there is a possibility that the 

 larva is able to detect sounds of different wave lengths. 



