1. Mandibles, first maxillae, and labium appear in the germband at an early stage.
2. The rudiments of the first maxillae unite to form the dorsal stylet, while those of the labium unite to form the ventral stylet.
3. The hypopharynx arises below the first maxillae or dorsal stylet; it becomes tubular and is transformed into the salivary duct.
4. The stylet sheath arises from the integument as a raised lip; it surrounds the dorsal and ventral stylets.
5. The labrum persists as the upper half of the buccal funnel.
6. The mandibles are throughout in a rudimentary condition; they disappear in the adult without becoming chitinized.