Survivorship of experimental cohorts of Mexican bean beetle, Epilachna varivestis Mulsant, was studied in three commercial dry bean (Phaseolus vulgaris L.) fields in 1995 and 1996 near Scottsbluff, NE. Mexican bean beetle survival was relatively low in 1995 but higher in 1996. In 1995, ≈50% of the egg masses did not hatch. The high egg mortality observed was likely related to drought stress of the host plants, because stressed plants turn their leaves over and expose eggs to sunlight. In 1996, environmental conditions were mild compared with 1995, and egg hatch was greater. Mortality of young larvae was lower than it was in the last two larval stages. The cumulative mortality ranged from 92.1 to 95.8% in 1995 and from 60.9 to 75.6% in 1996. No parasitized or diseased larvae were observed in the study fields or in those held for parasitism tests. Larvae from the same cohort (egg mass) were found distributed throughout a maximum range of 3.6 row-meter.