File:Fig. 2 Billen and Al-Khalifa 2018, sting apparatus w hindgut.png

Fig. 2. A. Scanning micrograph of the sting apparatus with attached hindgut (HG) and Malpighian tubules (MT) of B. sennaarensis worker. The venom gland consists of two free filaments (VF), a reservoir (VGr) with an internalized convoluted gland (visible in 1C) and a venom duct (VD) that opens through the sting (St). B. Detail of framed area in 1A, showing how both filaments fuse into a considerably thinner unpaired filament prior to entering the reservoir sac (white arrow). C. Semithin section through venom reservoir and internalized convoluted gland (CG) in B. sennaarensis alate queen. Note conspicuous supply of muscle fibres (MF). D. Ultrastructural detail (worker) of very thin cuticle-lined reservoir wall. E,F. Longitudinal and transverse semithin sections through the sting base of a worker, showing opening of venom gland duct (VD) and Dufour gland duct (DD). ct: cuticle, F: furcula, FC: fat cells, GS: gonostyli, MF: muscle fibres, NF: nerve fibre, SL: sting lancets.