Adult Phyllocnistis as a group are one of the smallest microlepidopteran leafminers, with a wing expanse of only 4-8 mm, similar in appearance to each other, with a silvery vestiture. Five Phyllocnistis species have hitherto been known in Japan. Recently, we described two new species: P. gracilistylella Kobayashi, Jinbo & Hirowatari, 2011 and P. shizukagozen Kobayashi & Hirowatari, 2011; and newly recorded P. unipunctella (Stephens, 1834) and P. chlorantica Seksjaeva, 1992 from Japan. We also reported their life histories and found above species have mining types new for the genus.

Larvae of Phyllocnistis species mostly utilize only one side (adaxial or abaxial) of the epidermis of the leaf, forming a serpentine mine. In the present study, we found that the Salicaceae mining species, P. gracilistylella and P. saligna occurred together, but differed in the position of the mines; the former utilized only the leaf, while the latter utilized the stem and the leaf and partly the leaf edge at the cocoon stage. On the other hand, the Chloranthaceae mining species, P. shizukagozen and P. chlorantica, utilize the both sides of the epidermis of the leaf, and the abaxial epidermis in the cocoon stage. Further we found a Moraceae mining unnamed species, which utilizes epidermis of the leaf vein and leaf stalk.