94 which extends from the lid 36 adjacent the pin the trigger 42 has a lower clearance wall 96 joined by a horizontal shelf 98 to a protruding upper wall 100 shown in fig1 and 2 the trigger 42 may be reinforced by outside ribs 102 running parallel to the shelf 98 as shown in fig4 a tab 104 extends downwardly from the trigger clearance wall 96 near the end away from the brackets 90 and is received within a tab guide hole 106 formed in the floor 52 of the base 28 a spring 108 is integrally molded to protrude from the base interior wall 46 which has a free end 110 shown in fig1 which engages the exterior of the trigger 42 and urges the trigger toward the strike member the integral spring 108 may be formed with an upper lead in ramp 112 to aid directing the trigger into place during assembly the upper wall 100 of the trigger 42 extends into the trigger compartment 82 to narrow the compartment to increase the likelihood that a rodent passing through the compartment will engage the trigger as shown in fig2 the strike member has a trigger engaging member 114 which projects from the strike member tunnel element 60 towards the trigger 42 the trigger engaging member 114.