1. The spring Cankerworm, Paleacrata vernata (Peck), has two pairs of prolegs on the abdomen, while the fall Cankerworm, Alsophila pometaria (Harris), has three pairs of abdominal prolegs

2. Apodous Larva: These larvae do not have either thoracic legs or abdominal prolegs (legless) e.g

3. The spring Cankerworm has two pairs of posterior appendages (prolegs); the fall Cankerworm has three.

4. The spring Cankerworm has two pairs of posterior appendages (prolegs); the fall Cankerworm has three.

5. Armyworm larvae may also be distinguished by a dark band on the outer side of each proleg

6. They have three pairs of legs at the front and six to seven pairs of prolegs at the rear.