The missing term in the series $1,5,11,19,29,\dots ,55$ is:

Let us look at the differences between consecutive terms in the series:
* $5-1=4$
* $11-5=6$
* $19-11=8$
* $29-19=10$

The differences form a sequence of consecutive even numbers ($4,6,8,10$). Therefore, the next difference must be $12$:

$$\text{Missing Term}=29+12=41$$

We can verify this with the final term by adding the next even number ($14$):

$$41+14=55$$

This matches the series perfectly.