1、The osmeterium is a defensive organ found in some caterpillars.
嗅腺器是一种存在于一些毛毛虫身上的防御器官。
2、When threatened, the caterpillar extends its osmeterium to release an unpleasant odor.
当受到威胁时，毛毛虫会伸展嗅腺器释放出一种令人不愉快的气味。