Abstract
Larval development of the yellow-spotted longicorn beetle, Psacothea hilaris (PASCOE), was examined at 25°C under two photoregimes of 15L:9D and 12L:12D using a population collected in Ino, Kochi Prefecture (west Japan type). Under 15L:9D, most larvae pupated after the 4th or 5th larval stadium, and the average larval duration was 51 days. Under 12L:12D, larvae molted about two times more than those reared under 15L:9D, and development was eventually arrested mostly at the 6th or 7th stadium. These larvae neither molted into the next stadium nor pupated for more than 150 days after the last molting. They were considered to be in diapause in super numerary stadia.
