Rhetoricians have introduced five criteria for the identification of allusion. The aim of this study is to verify the fourth and fifth criteria and to examine their efficiency since they have caused obscurity and confusion in recognition and identification of allusions and created inconsistency between the definitions and the nature of allusions. Regarding the correctness and effectiveness of the fifth criterion, it can be said that allusion is not realized in the form of words or compound words since it involves a compound image that is essentially embodied in an allusive proposition. This proposition enjoys a prime meaning with an actual or imaginary instance and hence it paves the way for the connotative meaning. Allusions, therefore, should be called allusive propositions. Regarding the efficiency and correctness of the fifth criterion, it can be argued that due to the imaginary and pictorial nature of allusion, its surface or prime meaning cannot always be realized in external world. Therefore, the prime meaning of allusion has sometimes an external instance and sometimes an imaginary one. Hence, according to the nature of prime meaning it could be said that there are three kinds of allusive propositions: pictorial allusive propositions whose prime and connotative meanings are realizable in the external world; imaginary allusive propositions whose prime and connotative meanings are imaginable or recognizable in imaginary world; and poetic allusive propositions which contain  metonymy, simile and metaphor and their prime meaning is realizable after uncovering the metonymies and metaphors. The prime and connotative meanings of this kind are realizable in the external world or imaginary world.