I like bugs, especially those in the superorder Dictyoptera. which includes cockroaches and mantises. i could tell you things about bugs for a very long time. of course, "bug" technically refers only to those insects in the order Heteroptera, known as the "true bugs"; i have only begrudgingly decided to use the word "bug" to describe animals in the class Insecta rather than "insect" because it is likely more people will understand what i am talking about. I am obliged to think that "bug" can be used casually to refer to any land-based arthropod or invertebrate. this means you could use "bug" to refer to a worm, a jumping spider, a lady beetle, or even an adult land hermit crab (i say "adult" because land hermit crabs do spend their larval stage as zooplankton underwater). now that i have made these points, you may be wondering about aquatic insects. you would think to call them "bug", although they are not land-based organisms. I think you could refer to an aquatic insect as "bug" because they had evolved from land-based animals. this also raises the question of crustaceans; i believe they are not bugs in my definition because they did not evolve from land-dwelling animals. with the exception of crustaceans that have evolved to live on land (such as isopods) they would not be bugs. in conclusion, I would call all land-dwelling arthropods (including aquatic insects and arachnids, although they are not land-dwelling) and perhaps other land-dwelling invertebrates "bug".