First, let's answer this nagging question: What's the difference between a muskmelon and a cantaloupe?

They're both ivory-yellow, solid and wrapped in fishnet rinds, but one's got seams, right?

Wrong, or at least not exactly, says Chuck Voigt, a vegetable specialist at the University of Illinois in Urbana-Champaign. The melon without seams is what many people call a cantaloupe, but technically it's not a cantaloupe, he says. It's really a muskmelon without seams, called a western muskmelon, which is different from an eastern muskmelon with seams, which is what most people call a muskmelon.

Got that?

"I don't know many people who have ever seen a true cantaloupe," Mr. Voigt says. "A true cantaloupe is really more like a casaba melon with no netting. It's an exotic melon grown in sub-tropical areas and rarely found here," he says. "It's like yams. True yams are found only . . ."

Hold it! Let's stick to melons. What is it most people are going to encounter in the way of melons when they're grocery shopping this summer? What are they all about?

Let's start with the western muskmelon -- that's the one without seams that people think is a cantaloupe. This is a melon you can buy almost year-round in the produce department. It's a shipping melon, Mr. Voigt says, grown in Arizona, Florida and places where the weather is mild.

"The marketplace is geared to the western-type shipping melon. Food service wants consistency, it wants solid flesh. But, really, it's a hard muskmelon," he says. It has corky textured netting with a fairly tight lace pattern.

On the other hand, the eastern muskmelon -- the one people actually call a muskmelon -- is loose-netted with definite seams or gullies.

"Traditionally, it has softer, sweeter, more melting orange flesh and is less shelf-stable," Mr. Voigt says. "Everything that makes it attractive to diners and unattractive to shippers," Mr. Voigt says. "A lot of eastern muskmelons come from southern Indiana, where they can be picked at a riper stage.

"Melons don't develop after picking. If they are picked early, they soften but don't ripen and won't get the extra kick of sugar from being left on the vine," Mr. Voigt says. "So in most instances around here, the eastern type is a better flavor bet. They start coming in July and keep up through the frost in late September and early October."

The eastern melons don't last as long: only about a week under refrigeration and about three days on the counter. Either way they are high in beta carotene, vitamin C and folic acid.

The ideal way to eat them is to buy them from a roadside stand right after harvest and eat them as soon as you get home. Barring that, look for one in the store that is firm but not rock hard. Find the blossom end (opposite the scarred end where the stem was broken off) and apply light pressure with your thumb. If it's mushy, the melon is starting to rot. If it's hard, it is too green. "It should just have some give," Mr. Voigt says.

Most muskmelons should show a "mellow yellow color" beneath the netting. One that's bright green was picked too early. A ripe fruit also should smell sweet, even the western variety, he says.

"If they smell like a pickle, they are green. If they have the aroma

of muskmelon wine, they're rotten."

Sweet honeydews

Honeydew melons, with their smooth ivory rind and lime-green flesh, can be almost too sweet when you get them very fresh and ripe. "That's how they get away with picking them green in Texas and shipping them up here," Mr. Voigt says. They are harder to grow than muskmelons, which is why the price seldom comes down.

If you are looking for the best honeydew, select one with a white to pale yellow skin that still remains firm when you press the blossom end. They should have a sweet, melony smell, rather than a musky odor. If the blossom end is soft or the skin too yellow, "chances are they've gone past," says Mr. Voigt.

"Watermelon is a pretty different critter," Mr. Voigt says. "All the other melons are hollow in the center with seeds contained in the cavity, but the watermelon is a totally different genus and species with seeds more distributed through the flesh. It also has a very hard, thick rind. It's almost as different as a squash."

The flesh color runs from white to yellow to pink to dark red, and the skin color can be white to almost dark green, often striped. The so-called seedless watermelon isn't really seedless, Mr. Voigt says. The seeds are just undeveloped so you can chew them up and swallow them.

Most people like to thump a watermelon to determine its ripeness, says Mr. Voigt. A good specimen should not sound mushy, nor should it give a hollow echo. A solid, deep resonance shows there is plenty of water and the flesh is firm.

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The following are some novel ways to prepare melon that your grandmother probably never heard of.

Grilled Chicken Salad With Melon Relish

Serves 4

juice of 3 large limes

1/4 cup honey mustard

3 tablespoons vegetable oil

salt, freshly ground pepper to taste

4 boneless, skinless chicken breast halves, about 1 pound

2 cups finely chopped fresh melon, such as muskmelon

1 cup finely chopped fresh jicama

1/2 red bell pepper, finely chopped

2 green onions, thinly sliced

2 tablespoons chopped fresh cilantro

1/4 teaspoon ground coriander seed

6 cups torn mixed lettuces

toasted sourdough bread slices

Reserve about 1 tablespoon of the lime juice. Mix remaining lime juice, mustard, oil, salt and pepper in small dish. Refrigerate half of the mixture for the lettuce.

Lightly pound the chicken breasts about 1/2 -inch thick. Coat with the other half of the mustard mixture in a pie plate or shallow dish. Refrigerate, covered, turning occasionally, for 1 to 4 hours.

For relish, mix melon, jicama, red pepper, onions, cilantro, ground coriander, reserved tablespoon lime juice, salt and pepper in a medium-size bowl. Let stand while cooking chicken.

Prepare a charcoal grill or heat the broiler. Grill or broil the chicken, about 6 inches from heat source, basting with the marinade, until nicely browned but still moist, 10 to 12 minutes. Remove.

To serve, toss lettuces with remaining half of the mustard mixture in a bowl. Divide among 4 serving plates. Top each with a chicken breast. Spoon melon relish over chicken and serve with toasted bread.

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Here's an appetizer adapted from Sarah Schlessinger's "500 Fat-Free Recipes," that uses fresh honeydew melon. It's also delicious with muskmelon.

Melon Bites Makes 4 servings

1/2 honeydew melon, seeded, skin removed, cut into 1-inch wedges or chunks

1/3 cup lime juice

1 1/2 teaspoons chili powder

Place the melon wedges or chunks, lime juice and chili powder in a bowl and toss well. Serve with knife and fork or wooden picks.

Per serving: 53 calories, 0.3 g fat, 0 mg cholesterol, 22 mg sodium.

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This colorful summer sparkler from the Dallas Morning News makes the most of watermelon. By pureeing it with tangy citrus and vodka --ed with ginger, you'll forgo the rivulets of juice running down your elbow.

Melonade Slush

Makes 11 servings

4 cups seeded watermelon cubes

1 can (12 ounces) frozen pink lemonade concentrate, slightly thawed

L 1 can (6 ounces) frozen limeade concentrate, slightly thawed

1/2 teaspoon grated fresh ginger

1 cup vodka, optional

2 bottles (1 liter each) club soda

mint sprigs for garnish

Place half the watermelon in a food processor bowl with metal blade or in a blender; process until smooth. Pour puree into a 2-quart, nonmetal freezer container. Repeat with remaining watermelon.

Add lemonade and limeade concentrates; stir to blend. Add ginger and vodka; stir to blend. Cover; freeze, stirring once or twice, until firm, 8 hours or overnight.

Remove from freezer 5 to 10 minutes before serving. For each serving, scoop 1 cup slush mixture into an 8-ounce glass; stir in about 1/2 cup club soda. Garnish with mint.

Per serving: 170 calories; 40 mg sodium; 0 g fat.

MORE MELONS

Here are a few other kinds of melons you might encounter:

Casaba: A yellow, ridged and warty melon slightly smaller than a volleyball with mild, greenish-white flesh. This is more like the true cantaloupe than the western muskmelon.

Canary: A bright yellow melon about the size of a large cabbage, this has soft, chartreuse flesh that tastes like a very sweet honeydew with overtones of muskmelon.

Crenshaw: Shaped like a large football, this melon has a very light green flesh with a very sweet, honeydew-like flavor.

Galia: A close-netted orange muskmelon with lime green flesh. The flavor is similar to an Eastern muskmelon with hints of honeydew and citrus.

Santa Claus: This is a large, oblong melon about the size of a small watermelon, but it is yellow with green streaks. The flesh is deep yellow-green with a sweet, full flavor reminiscent of citrus and cucumber.