I don't know what mantis means later, which means cicada.
The usage of "qi" includes:
The third person pronoun is equivalent to "he or she", "they or them", "it or them";
Demonstrative pronouns are equivalent to "that", "that", "those": others, the rest, followed by the style of the person;
Among them, only one is known, but not the other;
Conjunction, equivalent to "if" and "supposition";
Auxiliary words, indicating speculation, cross examination, order and encouragement;
End of word, after adverb: extremely happy.