The mealybug Phenacoccus aceris (Signoret) (Hemiptera Pseudococcidae) is a significant economic pest on grape as a vector of grapevine leafroll-associated viruses (GLRaVs) causing the damaging grapevine leafroll disease. To gain new insights into the feeding behavior and structural anatomy of this mealybug, the structure of the mouthparts was described using scanning and transmission electron microscopy and light microscopy. The piercing-sucking mouthparts of P. aceris are composed of a clypeolabral shield and a three-segmented labium with a groove on its anterior face containing the stylet fascicle. Fourteen pairs of different types of sensilla cover the exposed surface of the labium. The stylet fascicle consists of two mandibular stylets, with serrations on their distal extremity, surrounding two maxillary stylets. The maxillary stylets are interlocked and their coapted grooves delimitate the food and the salivary canals. No acrostyle-like structure was observed at the distal extremity of the maxillary stylets; instead, a specific ridge takes place. Stylet pathway was observed from the salivary flange on penetration site and then with the salivary sheath inside plant tissues up to the vascular tissues. This study provides new insights into P. aceris mouthparts and opens prospects for the study of the feeding behavior and the retention site of non-circulatively transmitted virions.