In the second part of Francesco Vitali’s email (first part here) that I received a few weeks ago, he clarified that the Philippine species of Euryphagus (Cerambycinae Trachyderini = Stenaspini = Purpuricenini) is E. pictus VOET 1778. As for E. maxillosus OLIVIER 1795 is a preoccupied name while E. nigricollis HELLER 1913 is said to be a variety.
Francesco then provided the following:
Genus Euryphagus THOMSON 1864
= Eurycephalus LAPORTE DE CASTELNAU 1840 nec GRAY 1831
pictus (VOET, 1778)
= maxillosus (OLIVIER, 1795)
pictus var. nigricollis HELLER, 1913
It should be noted that the species’ black marking on the prothorax as well as the end of the elytra is very variable and thus might confuse entomologists. Found from Luzon to Mindanao, sizes are also very variable. Photo above shows the male (left) and female (right).