INTERLOCKING MECHANISMS IN COLEOPTERA. 



295 



Fig. 8. Lateral portion of a cross section of the metathorax of Lacknosterna, 

 showing the parts affected by the contraction of musculus episternalis. X I5°- 



forcible detachment of the elytra. This pressure of the scutellum 

 is supplemented by the retraction of the prothorax against the 



