In order to examine the larval instar of Stenygrium quadrinotatum, the length and the width of head have been measured.
Four instar were admitted by the frequency curve and the correlative diagram. But the smallest group may be considered to be the second instar, judging from its own size and those of the last instar and the adult. If this infereace is right, the above-mentioned four instars become respectively the 2 nd_??_5 th instar.
The GAINES & CAMPBELL formula has been to fit in best with this case as the insect growth formula.