Final answer:
The writer's belief about flies is revealed in their appreciation for alliteration as a means to convey the rapidity and sensuality of flies in a stanza.
Step-by-step explanation:
The sentence that best reveals the writer's beliefs about flies from the provided passages is: 'Visually the use of alliteration is striking, particularly in the first line and almost equally so in the second.' This quote speaks to the poet's craft in using alliteration to differentiate the actions of the flies from the movements of other creatures, suggesting a recognition of their rapidity and a sense of sensuality in the poetry. This appreciation for the literary technique indicates the writer's belief in the expressive power of language to convey the unique qualities of flies amidst other elements of nature.