WITH THE dog days of summer upon us, most hunters are biding their time, looking wistfully ahead to the fall, when the air is crisp and winey and doves and mallards are thick as fleas. But it's right now that the varmint hunter is in his element, with groundhog "season" in full swing.

There actually is a year-round open season on "Marmota monax" both in Virginia and Maryland, but groundhogs are best hunted in relatively short grass not long after farmers have completed their haying chores -- that is, right about now.

There certainly are enough groundhogs to go around, and best of all, the price of a small-game license is about the only expense involved in hunting them. You won't need a special "duck stamp," National Forest permit or the like to go varminting; a simple "Got any groundhogs you want to get rid of?" often brings a smile and a yes from landowners.

Whether referred to as groundhogs, woodchucks, whistle pigs or other saltier epithets, there are few pests so roundly despised by farmers -- a definite point in your favor when seeking permission to hunt.

Groundhogs dig deep, sometimes partially obscured holes in pasture land, piling up mounds of dirt at the entrances. That plays hob with farm equipment and poses hazards for cattle, horses -- and riders.

One lady in Warrenton who stages summertime equestrian events goes so far as to place flags emblazoned with skull and crossbones in all the chuck holes she can find the day before such activities.

Groundhogs are two-foot-long members of the rodent family and can attain a weight of up to 14 pounds (although 8 or 9 pounds is more common). While they usually keep all four feet on (or in) the ground, they can and do climb trees on occasion.

For hunting purposes, though, it's wise to concentrate on fields of grass and clover (clover being the groundhog equivalent of a Big Mac). They also like alfalfa rather immoderately, and if you can find a field full of fresh alfalfa sprouts, you're in business.

You don't have to venture too far afield to find some primo groundhogging areas, either. While I've enjoyed fine groundhog hunting high in the foothills of the Blue Ridge, I have also successfully (and legally) hunted within sight and earshot of huge semis rumbling down Lee Highway in the northern part of Fauquier County.

Restrictions on the use of rifles make it a near impossibility to hunt groundhogs in Fairfax County. But top notch hunting can still be had in nearby Fauquier, Loudoun and Prince William counties.

In Maryland's Montgomery County, "shotgun only" is the rule, which pretty much precludes groundhogging there. But Prince George's and Frederick counties allow the use of rifles for small game, as do the counties on Maryland's eastern shore.

Individual towns in all the above jurisdictions may have restrictions on the use of firearms within their boundaries, however, so it's important to check with local officials before going on safari.

In addition to good eyesight and some camouflage clothing, the right type of rifle helps immensely. Some folks use any old smokepole for groundhogs, but a bolt-action .22- caliber centerfire rifle such as the .222 or .22-250 Remington is classic for the sport. Such rifles generally are mounted with telescopic sights of at least six-power -- important, since groundhogs are fairly cagey and generally are shot at distances of from 100 to 250 yards. There's nothing like a little pre-season practice on varmints, by the way, to get you in shape for that eight-point buck this fall.

Are groundhogs any good to eat? That's a point of considerable debate in these parts. Young animals grilled and basted with barbecue sauce are right tasty, in my opinion. But oldsters can be tough and somewhat greasy and must be stewed or subjected to slow cooking. Note: Groundhogs have musk glands under the forelegs which produce an unpleasant taste and odor with a half-life about the same as plutonium. Be forewarned: These must be removed before cooking. If you've never skinned or cleaned a groundhog before, it's probably best to watch someone familiar with the technique before attempting it yourself.

Then get out and go hunting while that hot, sticky, lovely groundhog weather is still with us.