Which combination defines the 2nd instar maggot stage?

• A. 5 mm long after 1.8 days
• B. 10 mm long after 2.5 days
• C. 14-16 mm long after 4-5 days
• D. 2 mm long after 0.7 days

Answer: (B)

The growth of maggots progresses through instars, with each stage defined by typical size ranges and approximate age after egg hatch. The second instar is usually reached when larvae are around 6–12 mm long, commonly occurring about two days after oviposition under moderate temperatures. So a maggot about 10 mm long at about 2.5 days fits this stage best. The other options describe sizes and ages more consistent with earlier or later instars: 5 mm at 1.8 days is still early first instar, 14–16 mm at 4–5 days points to a later instar, and 2 mm at 0.7 days is very early first instar.