Pretty much any woven nylon fabric will be mosquito resistant (it's my first line of defense). They tend to be less breathable than knit hi-tech fabrics, but I think the Thorofare were more tightly woven than some, and had no flaps for air circulation, so they were particularly sweat-retaining. Depending on where you hike, breathability of the shirt/pants may or may not be an issue. I'm guessing it's not desert, if you're inquiring about mosquitoes.
If you need highly breathable stuff and mosquito protection, permethrin treatment might be the answer.