- The larva is a white, segmented, worm-shaped burrower with black mouthparts (jaw hooks) in the narrower head region.
- For tracheal breathing, it has a pair of spiracles (air intakes) at both the anterior and posterior ends.
- Since insect skin will not stretch, the young small larvae must periodically shed their skins (cuticle) in order to reach adult size.
- There are two such molts in Drosophila larval development that are accompanied by shedding of the mouthparts as well as the skins.
- During each period between molts, the larva is called an instar, i.e. the first instar is between hatching and the first molt.
- Both the size of the larva and the number of teeth on the dark-colored jaw hooks are an indication of which instar the larva has reached.
- After the second molt, the larva (now third instar) feed until ready to pupate.
- At this stage, the larva crawls out of the food medium onto a relatively dry place, ceases moving, and everts its anterior breathing spiracles.
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