Architecture of a lamellicorn flagellum (Phyllopertha horticola, Scarabaeidae, Coleoptera, Insecta)

The distal three of the seven flagellar segments of the scarabaeid beetle Phyllopertha horticola are lamelliform, gathered into a club, and possess five sensillar fields that are packed with sensilla placodea. The most proximal surface of the club bears only hair‐shaped sensilla. On the inner four sensillar fields a narrow central elongated zone houses pit organs and cavities with sunken sensilla placodea and other sensilla. The most distal, fifth sensillar field is smooth. The sensilla placodea seem to be of several types. The only distinct difference between the sexes is the shorter and more rounded lamellae of the female. The total count of sensilla placodea in males outnumbers that of the females by about 60%.