The crystal structure and electronic properties of the δ-phase AgxV2O5 system, where 0.65 ≤ x ≤ 0.90, have been explored by means of x-ray four-circle diffraction and through measurements of lattice constants, electrical resistivity, thermoelectric power, magnetization and electron paramagnetic resonance. The structure of Ag0.68V2O5 has been redetermined with residual factors of R = 0.054 and Rw = 0.051. It is built up of V2O5 double layers and Ag ions located at two disordered sites between the layers. The δ-AgxV2O5 system is characterized against the composition as follows. For the range 0.65 ≤ x ≤ 0.75, first-order phase transitions with structural, transport and magnetic anomalies appear at Tc1 ≃ 220 K, below which, accompanied with significant reduction of the superexchange coupling constants, a nearly 1/6-filled compound has a spin gap originating from the trellis-layer model and other compositions probably remain paramagnetic with susceptibility maxima. For 0.80 ≤ x < 0.85, the only transport anomaly occurs at Tc2 ≃ 170 K, to which the crossover point is xc ≃ 0.775, and for 0.85 ≤ x ≤ 0.90, no anomaly exists there. The magnetic properties for 0.80 ≤ x ≤ 0.90 essentially exhibit linear-chain behaviours. The transport properties for x ≤ xc and x > xc are understood as indicating the hopping conductions of negative and positive small polarons, respectively.