Abstract: AnOberes fuscipennis(Chevrolat) usually completes a life cycle within one year in Sichuan province and Chongqing, southwest China. It spends thewholewinter in a formof ripe larva. Thereafterthe larva ofO. fuscipennisdevelops to its adult stage. This stage lasts relatively shorter than its larva stage, from the late April (ca20 April) tothe early July (ca10 July), with imagines takingthe veins ofmulberry and other plant leaves as food/nutrition sources, and laying eggs on the tips ofmulberry. The spatial pattern of the eggs shows a negative binomial distribution. The eggs are hatched for eight days and then the new larvae start to eat upwards the young tip of the mulberry leaves near the groovewhere the eggswere laid and hatched. Ashortwhile later, the larvae eat the mulberry leaves downwards for the availability of their food. Often, the larvae also turns upwards to eat the side branches, indicating that they intend to finish up the food source nearby before moving further. The larva stage is the longest period of its life. It can be as long as about tenmonths towards the nextAprilwhen it pupates. The pupa stage lasts about16 days. Duringthis stage theSpilopteron sp.starts to parasitize the larvae ofO. fuscipennis, and the rate of the parasitism can reach up to 37.1 % of the larvae before they start another life cycle.