SB 6.6.28
dandasukadayah sarpa
rajan krodhavasatmajah
ilaya bhuruhah sarve
yatudhanas ca saurasah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The sons born of Krodhavasa were the serpents known as dandasuka, as well as other serpents and the mosquitoes. All the various creepers and trees were born from the womb of Ila. The Raksasas, bad spirits, were born from the womb of Surasa.