Updated: July 20, 2025

Periodical cicadas are fascinating insects that have captured the curiosity of scientists, naturalists, and gardeners alike. Among them, the 17-year periodical cicadas are particularly notable for their unique and long life cycle. Understanding how to identify these cicadas, especially at their nymph stage, is crucial for enthusiasts and researchers who want to study or simply appreciate these remarkable creatures. This article will provide quick and effective identification tips for 17-year periodical cicada nymphs.

Introduction to 17-Year Periodical Cicadas

Periodical cicadas belong to the genus Magicicada and are well-known for emerging in massive numbers after spending 13 or 17 years underground as nymphs. The 17-year species are predominantly found in the eastern United States and have synchronized life cycles that make their emergence a rare and spectacular event.

The nymph stage of these cicadas lasts most of their lives , underground , feeding on root sap while developing. Recognizing them during this stage can be challenging because they do not have the distinctive adult coloration or sound but there are still telltale characteristics that help with identification.

Why Identifying Nymphs Matters

  • Ecological Insight: Understanding the nymph stage helps in studying their growth patterns and ecological impact.
  • Pest Management: While periodical cicadas aren’t harmful to humans, knowing their presence can aid in protecting young trees and plants.
  • Scientific Research: Identification assists entomologists in monitoring population cycles and distribution.
  • Natural Curiosity: For hobbyists and nature lovers, spotting nymphs adds depth to appreciation of this insect’s lifecycle.

Physical Characteristics of 17-Year Periodical Cicada Nymphs

1. Size

Periodical cicada nymphs are relatively large compared to many other insect nymphs. They typically range from 1 to 1.5 inches (25 to 40 mm) in length by the time they are ready to emerge as adults. Size is a helpful initial clue when identifying them amidst other soil-dwelling insects.

2. Body Shape

Their bodies are robust and stout, adapted for digging through soil. The thorax is broad while the abdomen tapers slightly toward the rear. Unlike adult cicadas, nymphs lack wings.

3. Coloration

Nymphs have a dull brownish or tan exoskeleton which may appear slightly translucent when freshly emerged from eggs or shortly before molting underground. The color darkens and hardens with age.

4. Legs Adapted for Digging

One of the most distinctive features is their front legs:
– They are large, strong, and spade-shaped.
– These legs have stout claws that allow the nymphs to dig efficiently through soil.
– The forelegs often look disproportionally large relative to the body compared to other insects.

5. Head Features

Periodical cicada nymphs have prominent eyes that appear black and bulbous on the sides of their heads. Their antennae are short but visible.


Behavioral Characteristics that Help Identification

1. Underground Habitat

Nymphs live underground feeding on xylem fluids from tree roots. If you find a burrow with a freshly emerged cicada nymph nearby, it is likely from a periodical cicada group.

2. Emergence Timing

Since these cicadas emerge in synchronized events every 17 years (depending on specific brood), finding clusters of nymph exuviae (shed skins) on tree trunks or vegetation during late spring or early summer strongly indicates Magicicada species.

3. Burrow Exit Holes

Cicada nymphs dig vertical exit tunnels about half an inch in diameter through soil or turf. These holes, usually open immediately before mass emergence, can be a clue to their presence below ground.


Differences Between Periodical Cicada Nymphs and Other Soil Insects

Distinguishing periodical cicada nymphs from other subterranean insects like mole crickets, beetle larvae, or annual cicadas can be tricky but focusing on key traits helps:

Feature Periodical Cicada Nymph Mole Cricket Beetle Larvae Annual Cicada Nymph
Size Relatively large (1-1.5″) Similar size or smaller Usually smaller/varied Smaller than periodical
Forelegs Large, spade-shaped for digging Also spade-shaped but differ in structure Usually not digging legs Less robust digging legs
Color Brownish/tan exoskeleton Usually darker brown White/cream (larvae) Lighter brown
Eyes Prominent black eyes on sides Small eyes Often no visible eyes Less prominent eyes
Behavior Underground on roots; mass emergence Underground but solitary habits Soil dwellers; varied feeding habits Underground; annual emergence

How to Collect Periodical Cicada Nymphs Safely

If you want to observe or study these nymphs, follow these guidelines:

  • Timing: Search just before expected emergence times in spring or early summer.
  • Location: Look near hardwood trees such as oak, maple, hickory, or elm where periodical cicadas prefer feeding.
  • Digging: Use small garden tools gently around suspected burrow holes without damaging roots.
  • Handling: Handle with care; they are delicate despite tough exoskeletons.
  • Release: After study, release them back near the collection site unless involved in scientific research.

Common Mistakes to Avoid When Identifying Nymphs

  • Confusing With Adult Cicadas: Adult periodical cicadas have prominent red eyes, wings with orange veins, and distinct black markings.
  • Assuming All Underground Insects Are Cicadas: Many insects live underground; focus on leg shape and size.
  • Ignoring Emergence Timing: The synchronized life cycle is key, ifs you find large numbers outside the predicted year it’s likely not a periodical cicada brood.
  • Overlooking Habitat Preferences: Periodical cicadas favor certain tree types; presence near non-preferred flora might indicate other species.

Final Tips for Quick Identification

  • Look for large size (~1-1.5 inches), spade-like forelegs adapted for digging.
  • Note brownish coloration with hardened exoskeleton.
  • Search near mature hardwood trees during late spring prior to mass emergence.
  • Find vertical exit burrows approximately half an inch wide.
  • Observe for clusters of shed exoskeletons on tree trunks or vegetation indicating recent emergence.
  • Compare with local insect guides focusing on soil-dwelling species in your region.

Conclusion

Identifying 17-year periodical cicada nymphs involves paying attention to specific physical traits such as size, leg shape, coloration, and habitat preferences combined with awareness of their unique life cycle timing. These insects play an essential role in forest ecosystems and provide exciting opportunities for observation due to their extraordinary life span underground followed by dramatic mass emergences.

By using these quick identification tips, anyone from amateur naturalists to professional entomologists can confidently recognize these intriguing insects before they complete their transformation into the winged adults that fill the air with their distinctive summer chorus every seventeen years. Whether you encounter them while gardening or during a field study, understanding how to spot periodical cicada nymphs enriches your connection with nature’s incredible rhythms.


Embrace the next emergence season equipped with knowledge , happy cicada hunting!

Related Posts:

17-Year Periodical Cicada