There were two insects in the bug jar this morning.
The first was a leaf miner larvae. It is a yellow larvae about a half inch long and, depending on the species, feeds on Swiss chard, spinach, cabbage, broccoli raab, potato, bean, tomatoes, peppers and beets.
You know you have them in the garden if the leaves of your plants have squiggly paths tunneled into them. To control, remove the infected leaf (insect is inside) and throw it in the trash.
For more information: http://plantdiagnostics.umd.edu/level3.cfm?causeID=266
The other insect was the larvae of a white cabbage moth, which attacks all brassicas.
The specimens in the jar were desiccated so I suggest you look online to find photos.
If you see them in the garden, pick them off and discard.