Few membracids are considered to be agricultural pests, therefore their feeding behavior has received little attention because most detailed studies of feeding have focused on agricultural pest species. The goal of our study was to investigate treehopper feeding using EPG combined with histology in the treehopper Umbonia crassicornis. We used these techniques to compare waveform types and feeding sites among three age groups of insects. In addition, we used these techniques to better understand how the feeding behavior of nymphs compares to adult feeding in U. crassicornis. We found that there are distinct sets of waveforms representing the feeding behaviors of each age group. In addition, we found that individual age groups exhibit unique probing durations and frequencies. We also found that U. crassicornis fed on both phloem and xylem, although each age group spent different amounts of time ingesting from each tissue type. Furthermore, examination of salivary sheaths showed differences in structure among age groups, with young nymphs producing incomplete sheaths made up of discontinuous salivary blobs scattered along the path leading to feeding tissues and older nymphs producing more complete sheaths directly into feeding tissues.