Dichotomous Key activity - Free Printable

Let's solve this step-by-step using the dichotomous key provided and match each insect (A–F) to its correct scientific name.

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🔍 Step 1: Understand the Dichotomous Key

This is a dichotomous key, which uses a series of paired choices based on observable traits to identify organisms. We follow the path through the key based on the characteristics of each insect.

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🐞 Insect A: Ladybug

- Wings: Not spread out (they are folded under hard wing covers)
- Antennae: Short
- Body: Red with large dark spots → 7 black spots

Follow the key:
1. b. The insect does not have wings that are spread out → Go to 4
2. a. The insect has stripes? → No, it has spots → So go to 5
3. a. The insect has large, dark spots → Coccinella septempunctata

✔ A = Coccinella septempunctata

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🐞 Insect B: Cicada

- Wings: Spread out (transparent, large)
- Antennae: Very short
- Wings: Two sets visible

Follow the key:
1. a. Wings are spread out → Go to 2
2. a. Short antennae → Go to 3
3. a. Two sets of visible wings → Chortoicetes terminifera

Wait! But Chortoicetes terminifera is actually a grasshopper, not a cicada. Let’s double-check.

But in the key:
- At step 3a: "Two sets of visible wings" → Chortoicetes terminifera
- Step 3b: One set → Musca domestica

But cicadas have two pairs of wings (forewings and hindwings), both transparent, so two sets visible.

So even though the common name might be misleading, we go by the key.

✔ B = Chortoicetes terminifera

Wait — but Chortoicetes terminifera is a locust or grasshopper, which doesn’t have wings like a cicada. There may be a mismatch.

But let’s continue with the key logic, not real-world biology unless needed.

Wait — look at the image: Insect B has large, veined wings, typical of cicada.

But in the key, Musca domestica (housefly) has only one pair of wings (hind wings reduced to halteres). So:

- If insect has two sets of wings, it should be Chortoicetes terminifera
- If one set, then Musca domestica

But cicadas have two pairs of wings, so B should be Chortoicetes terminifera

But wait — Chortoicetes terminifera is a grasshopper, not a cicada. That seems incorrect.

Wait — perhaps the images are not labeled correctly?

Let’s check all insects carefully.

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Let's analyze each insect visually:

#### A: Ladybug → Coccinella septempunctata ✔
→ Spots, no wings spread, short antennae → matches key.

#### B: Large, veined wings, body long, no obvious stripes, wings spread → likely cicada
But the key doesn't list "cicada", but Chortoicetes terminifera is listed as having two sets of wings.

But Chortoicetes terminifera is a species of locust (grasshopper), which has two pairs of wings (forewings leathery, hindwings membranous), so yes, two sets visible.

But cicadas also have two sets.

So if B has two sets of visible wings, and short antennae, then:

- Step 1a → Go to 2
- Step 2a → Short antennae → Go to 3
- Step 3a → Two sets of wings → Chortoicetes terminifera

So B = Chortoicetes terminifera

But visually, B looks more like a cicada than a grasshopper.

But since the key gives us only these options, and B has two sets of wings, it must be Chortoicetes terminifera

Let’s keep going.

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#### C: Beetle-like, no wings visible, compact body, no stripes, solid color

- Wings not spread out → Go to 4
- Does not have stripes → Go to 5
- Solid colored → Stenochidus gracilis

So C = Stenochidus gracilis

Yes — this looks like a ground beetle, possibly.

✔ C = Stenochidus gracilis

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#### D: Ant

- Wings spread out → Go to 2
- Antennae: long (elbowed) → So b. long antennae → Formica rufa

So D = Formica rufa

✔ D = Formica rufa

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#### E: Fly

- Wings spread out → Go to 2
- Antennae: short → Go to 3
- Wings: only one set visible (hind wings reduced to halteres) → So b. one set of visible wings → Musca domestica

✔ E = Musca domestica

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#### F: Louse (head louse)

- No wings → Go to 4
- Has stripes? No — it's solid-colored, but wait — does it have stripes?

Look at image F: It's a louse, small, no wings, no stripes, solid color.

So:
- Step 1b → Go to 4
- Step 4b → No stripes → Go to 5
- Step 5b → Solid colored → Stenochidus gracilis

But wait — C was already Stenochidus gracilis

Problem: Two insects cannot have same name

So there's a conflict.

Let’s recheck.

Wait — Step 5 says:
- a. Large dark spots → Coccinella septempunctata (already used for A)
- b. Solid colored → Stenochidus gracilis

But now both C and F seem to be solid colored, no stripes, no wings.

But C has wings folded (hardened elytra), F has no wings at all.

Wait — Step 1:
- a. Wings spread out → Go to 2
- b. Does not have wings spread out → Go to 4

So C has no wings spread out → Go to 4
F also has no wings → Go to 4

Then at step 4:
- a. Has stripes → Pediculus humanus
- b. No stripes → Go to 5

Now, F (louse): does it have stripes?

Looking at the image: F appears to have dark bands or stripes along the body → Yes, it has stripes

So F → Step 4a → Pediculus humanus

✔ F = Pediculus humanus

And C → no stripes → Go to 5 → solid colored → Stenochidus gracilis

So now:

- C = Stenochidus gracilis
- F = Pediculus humanus

No conflict.

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Final Check:

| Insect | Traits | Identification |
|--------|--------|----------------|
| A | No wings spread, spots → 4 → 5 → spots → Coccinella septempunctata | ✔ |
| B | Wings spread → 2 → long antennae? Wait — no! |

Wait — B has long antennae? Let’s check.

Insect B: Cicada-like → antennae are very short, almost invisible.

But in the key:
- Step 2: a. Short antennae → Go to 3
- b. Long antennae → Formica rufa

But B has short antennae, so should go to 3

Then at 3:
- a. Two sets of wings → Chortoicetes terminifera

So B = Chortoicetes terminifera

But D is an ant, which has long antennae, so D → Step 2b → Formica rufa

So D = Formica rufa

Now E (fly):
- Wings spread → 2
- Antennae: short → 3
- Wings: only one set visible → Musca domestica

✔ E = Musca domestica

F (louse):
- No wings → 4
- Has stripes → Pediculus humanus

✔ F = Pediculus humanus

C (beetle):
- No wings spread → 4
- No stripes → 5
- Solid colored → Stenochidus gracilis

✔ C = Stenochidus gracilis

A (ladybug):
- No wings spread → 4
- No stripes → 5
- Has large dark spots → Coccinella septempunctata

✔ A = Coccinella septempunctata

Wait — A and C both go to 5, but A has spots, C has solid color

So:
- A → 5a → Coccinella septempunctata
- C → 5b → Stenochidus gracilis

Perfect.

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✔ Final Answers:

| Letter | Insect | Scientific Name |
|--------|--------|------------------|
| A | Ladybug | Coccinella septempunctata |
| B | Cicada-like | Chortoicetes terminifera |
| C | Beetle | Stenochidus gracilis |
| D | Ant | Formica rufa |
| E | Fly | Musca domestica |
| F | Louse | Pediculus humanus |

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📝 Fill in the Word Bank:

```
A. Coccinella septempunctata
B. Chortoicetes terminifera
C. Stenochidus gracilis
D. Formica rufa
E. Musca domestica
F. Pediculus humanus
```

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✔ Answer Key:

- A: Coccinella septempunctata
- B: Chortoicetes terminifera
- C: Stenochidus gracilis
- D: Formica rufa
- E: Musca domestica
- F: Pediculus humanus

All match the dichotomous key and visual traits.

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🧠 Summary of Logic:

We used the dichotomous key step-by-step:
- Start at 1
- Choose based on wing position
- Then antenna length
- Then number of wings
- Then stripes
- Then spots vs. solid color

Each decision leads uniquely to one organism.

Even if some names don't perfectly match real-world appearances (e.g., "Chortoicetes terminifera" being a grasshopper but matching wing traits), we follow the key as given.

Thus, the solution is complete and consistent.