In the poem, "The Snake," by D.H. Lawrence, the snake might be seen as symbolic of evil or death—as is the snake of Genesis in the Bible that is so appealing, and yet so "deadly;" and the trees and plants and water of the poem may bring to mind the Garden of Eden.
The snake is presented as something powerful and admirable:
I felt so honoured...
For he seemed to me again like a king,
Like a king in exile, uncrowned in the underworld,
Now due to be crowned again...
And so, I missed my chance with one of the lords
The snake is beautiful:
Being earth-brown, earth-golden from the burning bowels of the earth...
We get the sense that despite the glory of the snake's color, the ease with which it moves, the captivation that the speaker feels in sharing the same space, and time spent with such an unusual creature, the snake is literally deadly—
For in Sicily the black, black snakes are innocent, the gold are venomous.
And as captivated as the speaker is, his "gut" is telling him that he should be afraid, while his ego accuses him that he is afraid.
The voice of my education said to me
He must be killed...
Was it cowardice, that I dared not kill him?…
And yet those voices:
If you were not afraid, you would kill him!
Whether we think of the biblical snake in the Garden of Eden who brought death to mankind, or simply remember the speaker's memories of Sicily that have taught him that this snake is deadly—obviously the more beautiful, the more deadly—the snake is symbolic of evil or death. For this reason, even as the speaker greatly admires the snake, his instinct drives him to kill it.
The poem may speak, also, to some innate inhumanity that man must practice against other creatures, but for me, his fear of death outweighs his appreciation for the snake's beauty, and the speaker listens to the warning voices from the past.