虫螻 (むしけら, mushikera) – worm; insect

回虫 (かいちゅう, kaichuu) – roundworm 

蚯蚓 (みみず, mimizu) – earthworm

百足 (むかで, mukade) – centipede

馬陸 (やすで, yasude) – millipede

蝿 (はえ, hae) – fly

蛾 (が, ga) – moth

猩猩蠅 (しょうじょうばえ, shoijyoi hae) – fruit fly (any insect of family Drosophilidae); vinegar fly; pomace fly; banana fly

蛆虫 (うじむし, ujimushi) – maggot

水黽 (あめんぼ, amenbo) – pond skater (any insect of family Gerridae); water strider

Check out parts 1 and 2 as well!