Fluttering moths were waking us at first light every morning as they tried to get out the high windows in our room, so late one night I devised a quick moth net from materials we had in the house. With a bit of adapting, it’s served us well.
It’s not glamorous, but it is effective, and harmless to the moths. One night, I caught over a dozen moths and let them go outside. They probably crept back in the next evening, but their breeding cycle didn’t last long and we were able to sleep through the night in peace without harming any.
I haven’t tried it on butterflies, but if you need to catch some, it should work with them, too (please make sure you release them unharmed when you’ve finished your photos/identifying).

Step 1: What You Need

• Old net curtain or piece of netting:
1) approx. 1 meter (3ft) x 46cm (1½ ft) and
2) approx. 30cm (1ft) x 18cm (7inches)
• Piece of thin stick, e.g. bamboo, approx. 2 metres (6ft) long
• Old wire coat hanger
• Duct tape/electrical tape
• Needle and thread
• Scissors

Step 2: Make the Top Part

a.Undo the wire coat hanger and form into a rough circle.

b. Thread one end of the wire in and out through the larger netting piece, along the longer side. You may need to push holes into the netting as you go. (If you want to be neat, you could make a hem along the netting, but the quick method works well).

c. Bring the ends of the wire together

d. Sew the short sides of the netting together.

e. Twist the ends of the wire together and tape with duct/electrical tape.

You now have the Top Part of the net. You can re-shape the wire to make a more regular top opening.

Step 3: Make the Bottom Compartment

Fold the small piece of netting in half, as in the picture, and sew up the sides to make a pouch (I used a sewing machine as it was handy, but hand sewing is fine).
This will be the Bottom Compartment.

Step 4: Join the Top and Bottom Parts

a. Run a gathering thread around the bottom of the Top Part, and
b. pull in until it’s the same size as the top opening of the Bottom Compartment. Do a couple of “knot stitches” to stop the gathering from pulling undone (take a stitch and pass the needle through the loop before you pull the needle all the way out).

c. This is the only tricky bit: tuck the bottom gathered edge of the Top Part inside the top opening of the Bottom Compartment.
Sew around the opening to join them together, with about 1/2” (2cm) of the gathered edge sticking out and down into the opening. (You might find it easier to turn both parts inside out to sew, as in the 3rd picture - so the extra edge will be sticking out before you turn it all back the right way).

d. This gathered edge makes a soft “flange” so the moth doesn’t just fly out again once it’s in the Bottom Compartment.

Don’t stress about this too much- as long as they 2 parts are joined together with a connecting opening – the “swish-and-flick” technique (described below) should secure the moth anyhow.
Note- My original net only had the Top Part, but this didn’t work as the moths flew out as soon as I caught them- so it’s worth adding the bottom bit.

Step 5: How to Use the Net

Your net is now ready to be taped onto the stick. That’s it - ready to use.

Instructions for use:

Firstly, you need to get the moth within reach. We have very high ceilings, and the moths usually rest in the daytime in high corners, out of reach.
I used a long bit of twig taped onto the end of a long stick as a “tickle stick” to encourage the moth out of its rest spot; once it’s flying around, it’s usually easy to get.

The “Swish and Flick” Technique: If you just swish the net past the moth and swoop the moth in, chances are it’ll just fly out again. You need to follow through the swish, swing the net around and do another long swish or two, then flick the net so the Bottom Compartment is flipped back over the rim of the net. Your moth will have been caught in the Bottom Compartment, and will now be trapped.
You just have to take the net outside, gently flip it open again and shake the moth out, unhurt.