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HOW to DRAW….. a beetle in 20 steps
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what you’ll need: piece of paper or sketch book
sharp pencil and a good eraser straight edge ruler note: some teachers may wish to demonstrate on a large sketchpad, a black/white board or with overhead transparencies.
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scutellum, which is part of the meso-thorax
Step 1. Have students place paper vertically. In the center of the page, draw a small equilateral triangle, pointing down (towards bottom of page). note: teachers can also use this to discuss ‘triangles’. Also, although it doesn’t yet look like a beetle:this triangle will become your beetle’s scutellum, which is part of the meso-thorax 8 x 11.5 piece of paper
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Step 2. Draw four straight lines
from your triangle as shown below. Two short lines, and two long lines. Notice that TWO lines originate at a right angle from the upper right corner of the triangle note: teachers can also use this to discuss RIGHT ANGLES
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Step 3. Connect the left short line
to the downward facing line with a long curved line. Do the same with the upper and right hand lines. these two shapes will become your beetle’s elytra
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Step 4. add one more long curve
that originates to the right of the triangle, and extends down, curving towards the bottom-most point. this line defines a region that will become 2 parts in your finished drawing: (1) the metathorax and (2) the abdomen
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ADDED mathematical subject:
variables x x x x teachers may wish to use variables to illustrate the similarities in some of the lengths.
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Step 4. draw a longer line, parallel
to the long horizontal line drawn in step 2. At the end, draw a curved line down and back towards the center of the page. The shape drawn should look like the front of a canoe or a blade. this region will define the beetle’s flight or hind wing, also called the metathoracic wing.
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Step 5. draw 5 parallel lines and
little circles above each one as shown below. these lines define the abdominal segments and the circles are the spiracles
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Step 6. draw a line, parallel to the top
of the original triangle (step 1) that extends left almost (but not quite) to the left hand edge of the drawing. Then connect it to the upper left corner with a curved line the region defined by these two lines will be the prothorax
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Step 7. The next few steps deal
with the beetle’s HEAD. To begin, draw three horizontal parallel lines above your drawing. The distance above should be approximately equal to one side of the original triangle and they should be positioned directly over the triangle from step 1.
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Step 8. add two small ovals on
each side of the lower line drawn in step 7. The ovals should connect this line to the line drawn in step 6. these two shapes will become your beetle’s compound eyes
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Step 9. connect the parallel lines
drawn in step 7 these two trapezoids will become your beetle’s clypeus and labrum
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Step 10 (halfway there). Add two
zig-zag lines up from the top of the beetle.
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Step 11. Connect the zig zags to
the lines drawn in step 9 with two curved lines. these two shapes will become your beetle’s mandibles
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Step 12. we’re going to focus in
on the head and add a set of antennae and some palpi start by adding two rectangles that emerge from the head above the compound eyes. Add a smaller square or rectangle on top of each these will be the first two segments of the antennae.The larger segment is the scape and the smaller one is the pedicel
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Step 12. we’re going to focus in
on the head and add a set of antennae start by adding two rectangles that emerge from the head above the compound eyes. Add a smaller square or rectangle on top of each these will be the first two segments of the antennae.The larger segment is the scape and the smaller one is the pedicel
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Step 13. beetle antennae are very
diverse – but most have 8-30 more segments on each antennae. The simplest one to draw is the filiform antenna. add a ‘tail’ like shape to the end of each pedicel and then subdivide this with lots of lines to make the segments. repeat on other side. this entire part of the antennae is called the flagellum
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Step 14. palpi. Under the mandible
of most insects (including beetles) is a small pair of what look like little antennae called maxillary palpi to add maxillary palpi- draw three contiguous ovals between the scape and the mandible. this entire part of the antennae is called the flagellum
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Step 15. legs. All insect legs
have 6 legs, each with 6 parts. But only 5 parts are usually visible from above. We’re only going to illustrate the LEFT legs in this drawing. each of these shapes is the femur of one leg. The plural of femur isn’t “femurs”…it’s: femora draw three rectangular shapes on the side of your beetle.
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Step 16. now add a longer rectangular to each of these each of these is the tibia of one leg.
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Step 17. on each tibia, we add
5 rectangles or ovals, that look like beads on a string. each of these strings is a tarsus and each segment (bead) is a tarsomere
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Step 18. on each tarsus, add two little claws each claw is called a pretarsus or tarsal claw
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Step 19. add parallel lines to
elytra grooves on the elytra are called striae
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Step 20. (optional) add remaining
legs.
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YOU’RE DONE!!!! CONGRATULATIONS YOU HAVE DRAWN A BEETLE!!!!
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step 1. draw a light vertical line about 1” from the RIGHT edge of you piece of paper. we’re going to erase this line in the next step
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erase these letters at the end..so do them lightly).
add 13 horizontal lines beginning about 1” from top and about ½” apart. NOW erase the line from the preceding step lightly letter these ‘A’through ‘M’ (we’ll erase these letters at the end..so do them lightly). A B C D E F G H I J K L M
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draw a line from the outstretched elytron to line F and write
B C D E F G H I J K L M Elytron
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inside the outstretched wing
place the word ‘Wing’ inside the outstretched wing A B C D E F G H I J K L M Elytron Wing
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draw a line from one eye to line C and write ‘compound eye’ A B C D E
G H I J K L M Compound Eye Elytron Wing
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right mandible to line A and write ‘mandible’
draw a line from the right mandible to line A and write ‘mandible’ A B C D E F G H I J K L M Mandible Compound Eye Elytron Wing
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right mandible to line A and write ‘mandible’
draw a line from the right mandible to line A and write ‘mandible’ A B C D E F G H I J K L M Mandible Maxillary palpus Compound Eye Elytron Wing
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right mandible to line A and write ‘mandible’
draw a line from the right mandible to line A and write ‘mandible’ A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Elytron Wing
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Either write the word ‘Pronotum’ inside the region to the left of the
elytron OR draw a line to line D and write the word ‘Pronotum’ there. A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum Pronotum Elytron Wing
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central triangle to line E, and write ‘Scutellum’
draw a line from the central triangle to line E, and write ‘Scutellum’ A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum Scutellum Elytron Wing
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Metanotum will go in line G with a line drawn to the region directly
right of the central triangle A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum Scutellum Elytron Wing Metanotum
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Metanotum will go in line G with a line drawn to the region directly
right of the central triangle A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum Scutellum Elytron Wing Metanotum Abdominal segments
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Metanotum will go in line G with a line drawn to the region directly
right of the central triangle A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum Scutellum Elytron Wing Metanotum Spiracle Abdominal segments
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little segments leading to line L these are labeled: Femur (J),
The parts of the leg can all be done at once with a line to the top segment going to J, the next to K, the claws at the bottom to M and then a bracket for the little segments leading to line L these are labeled: Femur (J), Tibia (K), Tarsus (L) & Tarsal Claw (M) A B C D E F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum Scutellum Elytron Wing Metanotum Spiracle Abdominal segments Femur Tibia Tarsus Tarsal Claw
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Body regions are denoted by large square brackets as shown here.
F G H I J K L M Mandible Maxillary palpus Antenna Compound Eye Pronotum HEAD Scutellum Elytron THORAX Wing Metanotum Spiracle ABDOMEN Abdominal segments Femur Tibia Tarsus Tarsal Claw
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last step is to erase the letters we put on the lines
to the right…and the lines themselves if you like you now have a scientific illustration of generalized beetle anatomy!!! Mandible Maxillary palpus Antenna Compound Eye Pronotum HEAD Scutellum Elytron THORAX Wing Metanotum Spiracle ABDOMEN Abdominal segments Femur Tibia Tarsus Tarsal Claw
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A legend can be added to to finish it off Scientific Illustration
Mandible Maxillary palpus Antenna Compound Eye Pronotum HEAD Scutellum Elytron THORAX Wing Metanotum Spiracle ABDOMEN Abdominal segments Femur Tibia Tarsus Tarsal Claw Scientific Illustration Beetle Anatomy (dorsal view) Student Name September, 2009
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