Some of the ectodermal cells insects are modified to form glands. These glands may be either integumentary, deep seated or endorine type. The integumentary glands secretions are either for protective or defense purpose, for alluring females or producing disagreeable odours, for forming protective covering or for respiratory functions. Deep seated glands are salivary glands, silk glands or accessory glands for reproductive purpose. Endocrine glands are associated with brain and perform moulting or reproductive functions. But, there are many glands whose functions are still unknown.