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My Wild Backyard and Vivariums

Making a Keep Box
My Critters
Feeder Insects
Terrarium, Vivarium
Critter Caresheets
Building Large Terrariums
Making a Keep Box
Making Outdoor Critter Houses
Backyard Pond Attraction
Wild Birds
Garden Insects
Butterflies and Moths
My Garden Plants
Wild Yard Plants
My Backyard Gallery
A Library of Links


3' tall and roughly 1' squared with a plexiglass table on the inside as a catch-all rest spot, just before a trap door bottom.


Window screen mesh lines the inside for foot holders with a plexiglass face.

Well, maybe not the prettiest box because I caulked all possible cracks with silicone rubber sealant, but it's almost done in two days work and looking allot better than I expected.

As far as my instructions, my dimensions are correct but my measurements are lacking a few quarter inches here and there. At any rate, it was easy to figure out with only a few extra times back to the puzzle saw because I erred.

In this particular case, I'm going to keep and raise house flies in there and I'll use them for example here. But, there's all kinds of critters I could keep in a box like that, including raise my own moths like cutworms. Virtually anything that doesn't eat wood, screen or glue.


Inside box with holes for soda bottles and plexiglass top. There is a 2" space between the back wall of the larger box and the length of this inner box.


1.5" holes are big enough to allow the bottle mouth without it slipping out or giving room on the edges for escapes.


The smaller box slips inside more or less like a dawer, with the sides giving it a snug fit against the inside by being slightly wider on the front end than the back. The front screw heads on the sides act as a stopper. Window screen mesh edged with duct tape acts like a skirt in front of escape areas along the hinges.


A plexiglass trap door attached by hinges (behind the duct tape) with a D-battery (x) on the bottom, inner side of the plexiglass to ensure it falls down when slipping the inner box out. Virtually, escapes are only possible by the bottle top holes.


Added a plexiglass bottom and flap open door with just a strip of duct tape inside and out to hold it in place. More or less to help keep the bottles in place.


I used duct taped window screen to make a flap over the holes the bottle tops go into. The tops push it open so flies have to get in or out from going under the mesh. Taking all the bottles out makes the flap go down, more as a deterrent of numbers than actually escape proof, I could have used board or plexiglass here as well.

The bottom of the box has a trap door with this inside box that can slip inside. Using soda bottles for my fly substrate where the larvae will reside, allowing the flies themselves to roam the rest of the box without escape. Alternately you could skip the soda bottles and just use this box with a bottom and a flip open lid. I went with bottles because the substrate I intend to put in it is nothing I want to have to clean out.

My final finish is a mosquito mesh netting on the top of the box like a cone shaped bag that I can use to gather the flies by shaking them from the netting into a panty hose stocking that has a paper towel roll inside of it to hold it open.

As far as feeding, the soda bottles of substrate are going to be a mix of peat moss and bloodmeal which is basically dry blood available in most gardening fertilizer supplies. For the flies themselves, I'm going to drill a small hole to allow a hamster feeder to sit on the side of the box and fill it with watered molasses so they can alternate the substrate with 'nectar'. Molasses contains cane sugar, which is as close to nectar as it gets. Red hummingbird feed doesn't cut it either, and is actually more harmful to hummingbirds than good.

I'm going to catch my first stock with the soda bottles of substrate to gather just the larvae. The biggest problem with flies and their possible diseases is the roaming from garbage can to dinner table. While there is no such thing as a sanitary or disease free fly even with buying fruit flies, I believe this box will keep them from breeding with the outside as well as me being able to control the diet.

3ft H
11" L
1ft W

Supplies Needed
*Roughly 1/2" by 5.5" boards - I got the cheapy pine from the lumber store.
*Roughly 1/2" by 2" boards
*Window screening
*Mosquito net mesh
*D - Battery
*2 small hinges
*Staple Gun
*Duct Tape
*Silicone rubber sealant - caulk gun

Cutting plexiglass, use the stove for heat and a kitchen knife with a smooth, unserated edge. It sounds like a chore and smells bad enough, but it isn't nearly as bad, labor and mistakes wise, as using a cutter. Make your lines with a sharp edge like a razor blade against a ruler. Follow the line with the heated knife on one side, turn it over and follow it again on the other side. Hold the piece down at both edges and give the piece you want off a gentle pull upward to see if it will easily break off along the line. If it doesn't, turn it over and make a deeper heat-cut and try again. If you try to make it come up too hard it might not crack off at the intended line. You have to make all straight lines, rather, if you want just a square out of it, you have to cut all the way down for a whole piece, then make the next cut for the square off of that. Otherwise, you can heat cut until you are all the way through the plexiglass.

Using plexiglass, pre-drill the holes you want to place the screws in with a bit large enough to allow all but the screw head. Take care to drill the screws down just enough to make it tight, the screw head pressing down too hard will crack the plexiglass. You can fix a crack with applying aquarium silicone glue or heating one cracked edge and re-applying it to the other. It's fairly good about sticking back but not completely forgiving. To stop a crack from furthering, drill a very tiny hole at the end that wants to spread and give it just a little heat or aquarium silicone glue.

I prefer the plexiglass but you can substitute other things like a thinner board or mosquito mesh netting for a clear view. The mosquito netting has much smaller holes than window screen, where gnats/fruit flies and other smaller critters like fly parasites and baby spiders can't get through. It's also flimsy and my cats might try to crawl on it so I'm going with the plexiglass.

Inside Box
A)*1 of the 5.5 - 9" L
B)*2 of the 5.5 - 8" L
C)*1 of the 2" - 9.5" L
D)*Plexiglass - 10.5"L 7.5"W

Making the Inside Box

A)This is the back board where the bottles fit in. 1" from the bottom of it and 1" from the side. Drill a hole of 1.5" circumference on both sides and a third in the middle.

B)Screw the side boards to the outside of A) and set it aside until the rest of the box is built, before you're ready to fix the trap door and put on the final plexiglass front.

C)Once you're ready, slip the box into the bottom and make sure this 2" board is long enough to fit inside the B) boards, to keep them snug against the walls but still be able to slide out. My own dimensions are A)10.5 W C)11" W

D)Once satisfied, lay the plexiglass over the top and pre-drill the holes the screws go in.

Making the Box

A)*6 of the 5.5 boards 3' height
B)*Bottom: 11" length, 11" width - I used 2 of the 5.5 boards
C)*3 of the 2" boards - 11.5" L
D)*6 of the 2" boards - 10.10" L
D2)*1 of the 2" boards - 3" H, 10.10 L
E)*1 of the 2" boards - 8.5" L

A)Set two of the 3' boards together and screw them in place to one side of the B) bottom board. Apply one of the C) 2" boards in the center outside or 19" from the bottom, across the two 3' boards.

Do this until you have all three sides screwed to the bottom board.

D) Apply four boards 2" from to the top on the inside

D2) Apply 3 boards approximatley 10" from the bottom on the inside, with the 3" Height one facing the front so you can screw the face plexiglass to it and apply hinges for the trap door. Place plexiglass on the top of it with about 2" free from the back. My dimensions for this plexiglass are 11" W, 8" L which is kind of a poop catcher and landing spot.

*Measure a piece of window screening to fit inside the box from inner frame and staple it in place so critters can use it for foot holding.

E)The plexiglass for the trapdoor is roughly 8" H, 11" W. Screw this board to 11" side at the very edge and center. Apply it to the bottom of the D) frame for hinges to be screwed in place on the E) and D) board. I duct taped a D-battery to the other end of this plexiglass on the inside to ensure it would fall down as a trap door when I take out the inner box as well as a little sanding for smoothness.

*Apply the smaller window screen mesh to the face of the hinges where there is a large escape area between the inner frame and trap door. My own dimensions are 7" H - 1' 1/2" L with the duct tape just covering the top of the trap door plexiglass.

*Fit the inner bottle box for testing and making sure it slides in tightly and the trap door falls with all three plexiglass surfaces allowing at least 2" before the back wall and the soda bottles tops themselves do not trap against the back wall.

*Apply the final plexiglass face to fit and screw in. You may want to caulk it with silicone as well as all the cracks between wood like I did mine. Breathing holes will come from the final mosquito mesh netting and the bottom inner box where you can just screen over an unused bottle hole.

*Set it upright and duct tape the top of the skirting window screen over the hinges to the face plexiglass and apply a final silicone caulking between the face plexiglass and the hinge boards from the inside. It should be so escape proof Houdini flea couldn't get out of there without taking advantage of the bottle holes.


Overall look with mosquito mesh netting top


Beginning, middle and end finish


Applying both window screen meshes. Inside, and a strip with duct tape in the front. Leave the top part of it free and duct tape it to the plexiglass face from the inside. Right pic, the final plexiglass face with a strip cut out of the bottom to allow the hinges room with lower corners over the larger escape areas the trap door makes.