S. Mahunka szerk.: Folia Entomologica Hungarica 61. (Budapest, 2000)

FOLIA ENTOMOLOGICA HUNGARICA ROVARTANI KÖZLEMÉNYEK LXI 2000 pp. 83-86 A stridulatory mechanism in Megymenum Guérin-Ménéville (Hemiptera: Heteroptera, Dinidoridae) J. D. Lattin A stridulatory mechanism in Megymenum Guérin-Ménéville (Hemiptera: Heteroptera, Dinidoridae) — Details are given of the stridulatory organ found in most genera now included in the Dinidoridae. Species of the genus Dinidor Latreille, confined to South America lack the stridulatory device. Key words: Hemiptera: Heteroptera, Dinidoridae, stridulatory organ. Many different taxa within the Hemiptera: Heteroptera have well-defined stridulatory structures, presumably for intraspecific communication (Leston 1957, Leston and Pringle 1963). Schuh and Slater (1995) provided an excellent review of the numerous types known to occur within the different groups of bugs and included appropriate references for these types. The basic system is a moveable part (plectrum) and a stationary part (stridulitrum) (Ashlock and Lattin 1963). These authors described a variety of stridulatory mechanisms found in the family Lygaeidae. A number of these combinations involved the hind femur or tibia as the plectrum and a striated areas on the underside of the abdomen or the outer edge of the fore-wing as the stridulitrum. Usinger (1954) reviewed the variety of such structures found in the family Aradidae where the types were so different from each other that he felt that these structures arose at least five times in the family. Each type is found in a different genus and at least two subfamilies are involved - the Mezirinae and the Calisiinae. The occurrence of a tibital plectrum and the edge of the abdominal connexiva, the stridulitrum, is common throughout most of the genera of the Dinidoridae and in both subfamilies. Some years ago, I noticed such a device in the genus Megymenum Guérin-Ménéville of the family Dinidoridae. The inner part of the hind tibia is enlarged and excavated on the inside surface (Fig. 1). Examination of the inside of this depression disclosed a series of circular impressions, each within a lightly defined hexagon (Fig. 2). This part of the insect is the plectrum. The edge of the abdomen is enlarged on each segment and forms the stridulitrum (Fig. 3) (Ashlock and Lattin 1963). Schouteden (1913) published an early and thorough review of the Dinidorinae and described the unusual modifications of the hind tibiae in some members of this subfamily. Yang (1936) illustrated a new species, Megymenum acutiangularis, from Bengkalis.