A cat (or 2) in the hand...
One of the good things about finding a bunch of eggs on a few adjacent fennel branches is that they were probably all laid in the same female fluttering session and are therefore the same age.
They thus all hatch at about the same time and grow up together as a happy family unit.
When they are getting near the roaming stage, it is fun to peel each member of this family unit off its respective fennel branch and place her/him on an open palm.
The sensation of many soft and slightly sticky caterpillar feet is a little strange, but nice!
Once you've learned to appreciate this special caterpillar sensory treat, be sure to try the same thing with garden snails...it's even better.
And that black dot is not melanoma; it's frass.