What causes the several irregular translucent areas in squash leaves?

Question

These are white net-like areas resembling what the skeletonizer does to grape leaves.

What causes the spots and what can I do about it?

Answer 1

Could be snails.  Do you see any snail trails?  If not then, here is way too much info on squash:

http://edis.ifas.ufl.edu/PI046

Answer 2

Probably bugs, they eat the green parts and leave the veins. But be careful with insecticides. Make sure that on the label it says it's OK for vegetables, even if you just spray it on the leaves. To be safe, I'd go with a more natural insecticide.