From the text, a witchetty grub represents either a moiety or an edible animal. 

A moiety is an exogamous, intermarrying group. The fundamental rule is that men of one moiety must marry women of the other.

Among the Native tribes of Central Australia, Witchetty grub men and women eat the grub very sparingly. They are not absolutely forbidden to eat it, but they must do so only in small amounts. This is because if they were to eat too much, their ability to successfully perform the Intichiuma would diminish, and the grub population would decline.

Conversely, it is equally important for them, especially for the Alatunja (tribal leader), to eat a little of the totemic animal, as eating none would have the same negative effect as eating too freely.

Alice Springs is considered “the most important centre of the witchetty grubs, where, amongst forty individuals, thirty-five belong to the Bulthara and Panunga, and five only to the other moiety of the tribe.”

The witchetty grub is also clearly an edible animal, as evidenced by an account from the northern tribe of central Australia which states that “when he had gone they came out again and walked about eating charcoal and witchetty grubs.”

According to the customs of the Natives of Central Australia, the grub must not be eaten like other food out in the bush, or the men of the totem would become angry and the grubs would vanish. 

After the Intichiuma ceremony, when the grubs become plentiful and fully grown, the Witchetty grub men, women, and children collect large daily supplies. They bring these into camp to be cooked until dry and brittle, after which they are stored in pitchis (wooden vessels) and pieces of bark. At the same time, those who do not belong to the totem are also out collecting.

The supply of grubs lasts only a very short time, as the animals appear after rain. When they grow less plentiful, the store of cooked material is taken to the Ungunja, or men’s camp, where all the men assemble, acting as usual under the instructions of the Alatunja. 

The natives survived on what the land provided–a rich and varied diet. As ethnographers Lorimer Fison and A.W. Howitt noted, food was “widely spread throughout the country, and included almost everything, from the larvae of insects to the great kangaroo.” They also consumed fish and birds.