Cold tolerance studies were conducted under laboratory conditions for cocoons of Allorhogas pyralophagus Marsh, a Mexican parasitoid of graminaceous borers. By storage, developmental time (from cocoon to adult emergence) could be extended by 2 to 6 times. However, cocoons stored for more than 14 days at 2 degree C failed to survive, while at 5 and 10 degree C, about 50% emergence was recorded for up to 21 days of storage. With respect to survival and adult longevity, 10 degree C seemed to be the most suitable storage temperture. Pre-emergence period was also significantly increased by storing cocoons for 21 to 35 days at this temperature. Sex-ratio of emerging adults was not significantly affected by storage. Fecundity was adversely affected in all the treatments except in the case of females emerging from cocoons stored at 5 degree C for 7 days. The progency of parasitoids which emerged from cocoons stored at 5 and 10 degree C for 35 days consisted of only males. It is clear from the present study that A. pyralophagus cocoons are more amenable to short-term storage. none