Grasshoper
Actual: 2 in
Magnified: 15 in
The scale factor is given by:

Black beetle
Actual: 0.6 in
Magnified: 4.2 in
The scale factor is:

Honybee
Actual: 5/8 in
Magnified: 75/16 in
The scale factor is:

Monarch butterfly
Actual: 3.9 in
Magnified: 29.25 in
The scale factor is:

Answer:
Grasshoper, Honybee and Monarch butterfly have the same factor scale = 7.5
Black beetle has a factor scale = 7