Skandapurana 5.205.984_36

5.205.984_36

etasmātkāraṇādrakṣā kriyate bhasmasambhavā ..
viprāṇāṃ bhojyapātreṣu śrāddhe kūṣmāṃḍajādbhayāt ..
nāgarāṇāṃ na vāṃchaṃti śrāddhe chidraṃ yataḥ śṛṇu .. 117 ..

For this reason, protection made of ashes is made / upon the food dishes of the brahmins at a śrāddha out of fear of the Kūṣmāṇḍas. / Hear why they do not seek a defect in the śrāddha of the Nāgaras: