Hyloicus centrovietnama
Very similar to Hyloicus pinastri, but differs in the following:hindwing less elongate; antenna proportionately longer; foretibia with fewer spines; midtibia with no spines other than sometimes some minute apical ones; hindtarsal 1st segment shorter than hindtibia, as long as segments 2-5 together; hindtibia with long apical spur less than half the length of 1st hindtarsal segment. Forewing upperside darker brown than Hyloicus caligineus sinicus, which is more grey-brown, and Hyloicus caligineus brunnescens, which is intermediate, having both greyish and brownish forms.
Male genitalia: Similar to those of Hyloicuspinastri, but: uncus longer and much narrower; gnathos sinuate, more obviously so than in Hyloicus caligineus sinicus, not completely divided mesially; valve more rounded; harpe with both processes shorter, the dorsal one branching from the dorsal margin of the other and longer than in Hyloicus caligineus sinicus, curving dorsad apically; phallus with apical process longer, much longer than in Sphinx caligineus sinicus.
Female genitalia: Ostial plate with lobe proximal to ostium longer and narrower than in Hyloicus pinastri, but individually variable.
There is a specimen in CMNH currently identified as Hyloicus caligineus brunnescens and labelled "P. I., Isl. of Gunmares", which is interpreted to be Guimaras Island in the Philippines. The identification of this specimen should be rechecked but if it does prove to be Hyloicus centrovietnama, then the locality is most probably erroneous. It is not mapped here.