The fashion world for summer is that underwear is out. Not in the way you think -- it hasn't gone out of fashion -- it's no longer inside but outside. Those chemise tops and little bodices that look like Victorian whaleboned corsets have come out from underneath.

At the Adri fashion show last fall, the word was knitted tops shaped like men's undersirts and worn under loose-fitting organdy jackets. This simple top is an exact replica of a man's undershirt, done in bold plain knitting in lilac, coffe, ivory and caramel.

If you're uneasy about wearing underware as outerwear, don't be. But soft, flesh-colored strapless bras are available. So but a package of undershirts -- the usually come three to a pack -- and create. Just wash then first to tliminate shrinkage later on.

A white cotton undershirt is a blank page. You can dye it, decorate it with indelible marking pens or trim it with anything. Applique them, using bits of lace, eyelet or printed motifs cut from yard goods or handkerchiefs. Attach these adornments with traditional applique technique, machine zigzag or even on of the webs such at Stitch Witchery.

And last but not least, undershirts make a wonderful canvas for embroidery. Just remember the knitted fabric stretches, so be sure to stablize it first by mounting a piece of soft woven fabric, such as batiste, into an embroidery frame, then baste the undershirt on top and sew through both layers.

In some cases, you can trace the design on the backing itself; the lines will show through. Or you can always copy the design directly on the undershirt with a washable Trace-Erase pen. Then get out the floss and embroider, remembering to cut away the excess backing when you've finished. You don't have to be an experienced needleworker. Even the simpliest of stitches -- like the lazy daisy -- can be most effective when scattered across a summer shirt.

But the most fun of all is to collect laces, crocheted doilies, ribbons and woven trims, and use them to tranform your undershirt into a thing of beauty. Why not cut off the straps and replace them with a lace trim or strand of pastel ribbon? Another idea is to add a lace border to the hemline and armhole edge. If you have an interesting doily or piece of lace you would like to recycle, applique it to the top of the bodice. Depending on your shape (and your nerve) you can even cut away the T-shirt fabric from under the lace and let more of you show through.

Q. I'm always left with armfuls of extra yarn at the end of my crewel projects. Is there any way of knowing from the start just how much I'll need?

A. Unless you know in advance what kinds of stitches (and in what color) you'll be using, it's difficult to be exact. There is a mathimatical way, if you have the skill. Work a 1-inch square on your canvas, and note the amount of yarn used. Figure the number of square inches to be covered by each color of your design, then multiply by the amount used to work the 1-inch square. This will give you the approximate yardage for each color and mere handfuls left over.

Q. I do alot of embroidery -- always in a frame. Now, after a week or so I've finished stitching and the hoop has left a dark, noticable circle. What can I do?

A. First of all, always remove the hoop when you're not stitiching. That's the ounce of prevention you need. If you must leave the hoop on, put your work in a pillowcase so that loose dirt can't settle on it. If you're using a plastic hoop, you should wrap the inner ring with bias tape first. If you're stitching on delicate material (silk, velvet), put some sheets of tissue paper over the material in the inner ring, then lay the outer ring over, tearing the paper away, leaving a nice padding.