This paper deals with the saltatorial mecanism of the halticinae beetle Homophoeta sexnotata (Chrysomelidae). The apparatus lies in the femur and consists of a S-formed bent plate of cuticular material and a triangular smaller one both plates originating from the tendon of the abductor respectively of the flexor of the tibia and still hanging together with these. When the musculus flexor tibiae is contracted the triangular plate enters into the femur until its external edge is caught in a cavity of the inner side of the wall of the femur; simultaneously the bent plate that represents an enlargment of the tendon of the musculus abductor tibiae, becomes more dilated, causing a strong tension in it. During the relaxation of the flexor the tension in the bent plate only effects on the triangular plate which now remains fixed in the cavity. This plate, an enlargment of the musculus flexor tibiae, prevents the backward movement of the tibia. When now the abductor is contracted, the tension in the bent plate will encrease because of its extremily is rising a large tendon on which is fixed the larger part of the abductor. Moreover, three other parts of the abductor are fixed directly or by means of a tendon on the sides of the plate. These muscles are called dilatatores. The tension which will lead to extend the tibia for jumping of the beetle, cannot effect on the articulation jet because the triangular plate prevents every movement. On the summit of the contraction of the abductor a transverse edge of the bent plate is pressed against the triangular plate, this is slowly shifted to the side and at last jerks, suddenly out of its bed. Now all the accumulated tension, intensified by the contractive power of the large abductor, reacts upon the articulation of the tibia. The tibia extends with a violent power and shoots the beetle for some meters ahead. during the jump the insect opens its wings to fly independently. Biologically considered, this apparatus offers to the animal a great advantage: In danger the beetle takes off immediatly without losing precious time for opening the wings. The organ is generally found in halticinae. In honour of the great Brazilian entomologist PROF. DR. ANGELO DA COSTA LIMA this organ is proposed to be called the "ORGAN OF COSTA LIMA".