UA 3914 then UA 4313 at Houston
Chicago → Houston → Harlingen
Timetable, Houston time
23:27UA 3914 from Chicago at the gate
18:25UA 4313 to Harlingen leaves the gate
18 h 58 apart on the timetable, overnight
UA 4313 leaves 18 h 58 after UA 3914 arrives on the timetable: more than half a day, so not a connection we count.