Figure 1: Representative drawings of the large wax glands (sensilla sagittiformia = arrow-organs) in nonfed adult females of R. sanguineus. Top: direct view looking down on the pore opening of the gland. Bar m. This transverse view of the gland opening shows the fringe (Fr), the spongy elastic chitinous frame (F), the border of the pore opening (B), and the top of the valvular arm (V), that make up the roof of the tuft chamber. Bottom left: redrawing of the original 1942 description of the sensillum sagittiforme in sagittal view from Hyalomma marginatum Koch by Schulze  (also redrawn in Dinnik and Zumpt ). Bottom right: drawing of the large wax gland from the present study (redrawn from Figure 2(a)). Labeled structures: pore opening of gland (Po), distal arrow-shaped duct (D), valvular arm of the roof of the tuft chamber (V), tuft (T), tuft chamber (Tc), anchoring filament of the tuft (Fa), knot of the scolopale (K), spongy elastic chitin (S), projecting edges of the scolopale (P), proximal terminal chamber (Pc), axial sensory nerve fiber (A), hypodermis (H), glandular cells (G), and enlarged juxtapositioned transdifferentiating epithelial cells (*). Bar m.