There are multiple metric units to choose from! This tutorial goes through the process of choosing the best metric unit to use for measuring the mass of a given object.
The most common aphids on houseplants are the light green ones (pear aphids), but aphids can also be found colored pink, white, grey and black. Additionally, winged aphids can appear when colonies are established and fly to infect new plants. Juvenile aphids (nymphs) look like smaller versions of the adults.
Bumble bees are easily recognized, being large (3/4 inch long) with black and yellow or orangish hair patterns on their abdomens. Paper wasps are 3/4 to 1 inch long, slender, narrow-waisted wasps with smoky black wings that are folded lengthwise when at rest. Body coloration varies with species . Baldfaced hornets are up to 3/4-inch long with black and ivory white markings on the face, thorax (middle body part) and tip of the abdomen.