Fig. 4. PETH-immunoreactive Inka cells (stained orange/red) in different developmental stages of Holometabola. Numerous small, simple Inka cells attached to tracheae of pharate larva of the alderfly Sialis (A) and pharate pupa of the antlion Myrmeleon (B). (C,D) Pharate larvae of the water beetles Dytiscus and Laccophilus contained a large number of mostly coupled Inka cells with cytoplasmic processes. (E,F) Small and large types of Inka cells in the mealworm beetle Tenebrio. Small cells were scattered throughout tracheae of pharate adults (E); broad trachea near the abdominal spiracle contained two large cells with processes and two small cells in one-week-old adults (F). (G,H) Epitracheal glands, each containing one immunoreactive Inka cell and two smaller cells in dipteran pharate larvae of the mosquito Aedes (G) and cranefly Tipula (H). Note that Sialis, Myrmeleon and Tenebrio contain many variable Inka cells scattered throughout the tracheae, while only 18 pairs of oval epitracheal glands, each containing one Inka cell, are segmentally distributed along the major trunks of lateral tracheae in Diptera. Scale bar, 50 µm in A—D and G—H; 100 µm in E.

Return to article