Belostoma lutarium (Stål) is semiaquatic predator common to vegetated ponds, lakes, and bayous throughout eastern North America. We used scanning electron microscopy and histological cross sections to show that the morphology of the feeding structures of B. lutarium agrees with the general hemipteran feeding plan. Slight deviations from the previously reported observations for other Nepomorpha include the structure of the triturating devices, feeding stylets, and the efferent salivary duct. Furthermore, interrupted feeding trials indicate that B. lutarium is able to feed on large prey for over 2 h and not deplete its supply of salivary enzymes. All three productive components of the salivary gland (main, lateral, and accessory glands) empty most of their salivary products during the first 2 h of feeding, and begin regenerating their secretions during the feeding process. Essentially, no latency period for saliva production exists in this species. The structure and function of the mouthparts and salivary gland are adapted for the predaceous feeding habits of Belostomatidae.