Early in the novel (chapter 3), Mrs. Moore returns from the club and sees a small wasp asleep on a coat peg. She does not disturb it. Indeed, she seems to feel quite affectionate toward it, addressing it as "Pretty, dear." The wasp is a symbol of the unity of all life, as understood in the Indian religious tradition. Everything, even an insect, is a manifestation of Brahman. Mrs. Moore does not know this intellectually, but she is sympathetic to the idea of the oneness of the universe. Her reaction to the wasp shows she is in tune with this way of thinking.
In the next chapter, the image of the wasp occurs again. The two English Christian missionaries, Mr. Graysford and Mr. Sorley, are in the habit of discussing the extent to which the animal kingdom might share in divine bliss (presumably after death). They discuss this question with their Hindu friends. Mr. Sorley believes that monkeys might be so blessed, but he is less sure about jackals, even though he thinks the mercy of God might well extend to all mammals. But he is uneasy, as a Christian, about extending this to wasps.
The third occurrence of the wasp image occurs in Part 3, when Professor Godbole is performing the religious ceremony. Into his mind at almost the same time drift the images of Mrs. Moore and of a wasp, two images that "melt into the universal warmth." Since there is no sign that one is worth more than the other to him, this suggests the difference between the Indian and the Christian view of things.
The green bird that Ronny and Adela observe and try to identify but cannot (chapter 8) symbolizes India. India is elusive; it cannot be neatly categorized. Categorization is the Western, but not the Eastern, approach to understanding. It relies on rational understanding, and is part of the scientific approach. But as far as India is concerned, "nothing is identifiable, the mere asking of a question causes it to disappear or to merge in something else." This is why India will always baffle and defeat those Westerners who seek to understand it. The Indians have a different attitude to understanding, as is shown in the following chapter, when Aziz recites poetry. The poetry reminds the Indians that India is one, a unity, but they grasp this at the level of feeling, not of intellect.