Irulandi, S., Kumar, P.K.V., Seetharama, H.G., & Sreedharan, K. 2001 Biology of Horniolus vietnamicus - a newly recorded coccinellid predator of the coffee mealy bug, Planococcus lilacinus (Cockerell).. Journal of Coffee Research 29(1/2): 18-24.

Notes: The biology of Horniolus vietnamicus was studied. A morphometric analysis of different developmental stages of the beetle was conducted. The adult is a small black beetle with four orange spots on the elytra. The female beetle laid, on average, 21.63 plus or minus 12.14 eggs among the mealybug colonies. The eggs hatched in 5-7 days. There were four larval instars lasting 18-23 days. The pre-pupa stage and the pupa stage lasted for 4-5 days and 10-15 days, respectively. The mean adult longevity in the laboratory was 56.07 days. The total life cycle was completed in 37-50 days at a mean maximum and minimum temperature of 27.49 plus or minus 7.93 and 16.95 plus or minus 3.30 deg C, respectively, and a mean relative humidity of 61.58 plus or minus 23.24%. It appeared to be a poor predator, with each adult feeding only on 10-15 mealybugs during its average lifespan, and each grub consuming 5-20 mealybugs.