The first 'true' abdominal segment, which in apocritan Hymenoptera is fused to the thorax as the posteriormost section of the mesosoma. [drawing

The first segment of the abdomen of Hymenoptera, which is fused to the posterior end of the thorax and which appears to be a thoracic sclerite (Fig. 62A).

The propodeum is found in Hymenoptera (the wasp order). It is the first abdominal segment which is closely associated with the thorax. Because of this, in Hymenoptera, the middle body segment is called the mesosoma since it contains three thoracic segments and the first abdominal segment. The rear body section is either called the gaster or the metasoma. It refers to the remaining abdominal segments.