Verified answer

Your pics are out of focus so I can't see what they are, but they could be squash bug nymphs. Here's a pic for comparison. This is a pic of squash bugs in various stages of growth. If your bugs look like these then your plant may be doomed. They carry a virus that causes bacterial wilt. I know this be cause I lost all my pumpkins last year from them. You can try to pick them off and throw them into a pail of soapy water or try spraying them with soapy water. Anyhow, here is that pic and another for identification:

http://www.vegedge.umn.edu/mnvegnew/IMG/Lsbleaf.jp...

http://www.forestryimages.org/images/768x512/12430...

Management and control:

http://www.vegedge.umn.edu/vegpest/cucs/squabug.ht...

Good Luck

It looks like they are small enough that they shouldn't do anything bad... if your leaves start looking chewed then i would worry.. also if they get any bigger they could be vine borrers. Vine Borrers tunnel through the vines eating it from the inside and ruin the pumpkin.

good luck!