The father, finding no purchase for his legs, clutches the ball, grows on to it, so to speak, thus adding his weight to that of the burden, and awaits events.

The effort is too great to last.

Ball and beetle fall together.

The mother, from above, gazes a moment in surprise, and suddenly lets herself fall, only to re-embrace the ball and recommence her impracticable efforts to scale the wall.

After many tumbles the attempt is at last abandoned.
Even on level ground the task is not without its difficulties.