The effect of topical application with 5,10 and 15 $mu$g/ ml androstenedione and methyltesterone to the fifth stadium larvae of the si1kworm,B. mori on fat body glycogen, protein, tota1 lipids, phospholipids, neutral lipids and haemolymph trehalose and protein has been studied. The fat body glycogen increased significantly in all the treated groups except in the 15$mu$g/ml androstenedione treated group. However the fat body glyco- gen increased significantly in 10 ${mu}g$/ml methyltesterone treated group. The androstenedione treated groups showed increased haemolymph trehalose but the increase was not significant. However the haemolymph trehalose increased significantly in all the methyltestosterone treated groups. The fat body protein decreased in all the androstenedione and methyltesterone treated groups except 15 ${mu}g$/ml methyltesterone where the decrease in fat body protein was significant. Whereas that of haemolymph protein significantly decreased in all the groups except in the group treated with 5 ${mu}g$/ml androstenedione where the decrease was not significant. The total lipids, phospholipids and neutral lipids of the fat body decreased significantly in all the groups treated with androstenedione and methyltestosterone when compared with those of carrier control.