The propodeum is the first abdominal segment in Apocrita Hymenoptera (wasps, bees and ants). In Vertebrates such as Mammals the abdomen (belly constitutes the part of the body between the Thorax (chest and Pelvis. Hymenoptera is one of the larger orders of Insects comprising the sawflies, Wasps Bees and Ants The name refers to A wasp is any Insect of the order Hymenoptera and suborder Apocrita that is neither a Bee nor Ant. Bees are flying Insects closely related to Wasps and Ants Bees are a Monophyletic lineage within the superfamily Apoidea Ants are social Insects of the family Formicidae and along with the related families of Wasps and Bees belong to the order It is fused with the thorax to form the mesosoma. The thorax is a division of an Animal 's body that lies between the head and the Abdomen. The mesosoma is the middle part of the body or tagma, of Arthropods whose body is composed of three parts the other two being the Prosoma and the It is a single large sclerite, not subdivided, and bears a pair of spiracles. A sclerite ( Greek skleros meaning " hard " is a hardened body part Spiracles are small openings on the surface of some Animals that usually lead to Respiratory systems In Elasmobranchs ( Sharks and It is strongly constricted posteriorly to form the articulation of the petiole, and gives apocritans their distinctive shape. In Entomology, the term petiole is most commonly used to refer to the constricted first (and sometimes second Metasomal segment of members of the Hymenopteran