Description of larval instars of the madicolous species Hydrotarsus compunctus (Wollaston 1865) is presented including a detailed chaetotaxic and porotaxic analysis of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. Compared to other genera of the tribe Hydroporini, Hydrotarsus Falkenström (1938) is postulated to be more closely related phylogenetically to Sanfilippodytes Franciscolo and Hydroporus Clairville based on the following combination of characters: (i) absence of the primary seta MX5, (ii) absence of a constriction at level of occipital suture, (iii) presence of a maxillary cardo, (iv) insertion of the primary seta MX1 on the maxillary cardo, (v) presence of spiracles on mesothorax and abdominal segments 1–7, and (vi) presence of the primary seta TR2.