second-instar

The second larval instar begins at the first larval molt and ends at the second larval molt. Larvae are actively feeding and crawling in the food. Distinct anterior spiracles are present as enlargements at the end of the tracheal trunk, but not open to the outside; posterior spiracles have three openings each, and four groups of small unbranched hairs. The salivary glands extend to the first abdominal segment, and have cells that are uniform in size. Mouth hooks typically have two or three teeth. Duration at 25 degrees C: approximately 23 hours (49-72 hours after egg laying; 25-48 hours after hatching).[ FlyBase:FBrf0007733 ]