马尾松毛虫２～４龄幼虫，按体背倒伏鳞毛及各体节的斑纹形状和颜色，可以分为两种类型。体背倒伏鳞毛为浅黄色，第２～６个腹节背面各有一黄色斑纹，明显成亚铃形的黄色型；体背倒伏鳞毛为灰黑色，亚铃形斑纹为暗黄色的黑色型。４龄幼虫经脱皮变成５龄幼虫后，体背的亚铃形斑纹不再存在，但体背倒伏鳞毛的颜色不变。调查结果表明，林分的虫口密度与幼虫的色型比有关。黑色型幼虫食叶量较大，蛹重较重，产卵量较大。色型比对松毛虫灾害的测报有意义。 Masson pine caterpillars 2 to 4 instar larvae, according to the body back lodging scales and the streaks of each section of the shape and color, can be divided into two types. Body lodging lint scales light yellow, 2 to 6 abdomen on the back of a yellow markings, apparently sub-yellow-shaped beard-shaped body lodging scales gray gray-black, yellow bell-shaped bell-shaped black type . After the 4th instar larvae became peeled into 5th instar larvae, the body-bellied beak stripes no longer existed, but the color of the body lodging scales was unchanged. The survey results show that the density of insect population density and larval color ratio. Larvae larvae larger amount of leaves, heavier pupae, larger fecundity. Color than the pine caterpillar disaster measured significance.