Significantly moreInopus rubriceps(Macquart) males fly beneath rather than above 54 cm, irrespective of crop height. In clearings fewer males were trapped at each successive height interval, namely 16–54, 82–121, and 148–186 cm above the ground. Within a 2.5-m-tall crop, no significant difference was detected in the number of males flying at the 2 higher intervals. Traps baited with virgin insects failed to attract either sex. AdultI. rubricepswere not observed to exhibit a strong color preference; but red traps caught significantly fewer flies than did traps of any other color tested. Sticky traps revealed that since the last survey,I. rubricepshad spread ca. 1.7 km into previously uninfested regions. Two species of dragon flies and 1 species of frog were found to be preying onI. rubricepsadults. 92.3% of eggs oviposited by wild females subsequently hatched. Significantly more soldier flies pupate under weeds than in soil exposed to the sun.