Formulae for the standard deviation. Whilst it is not necessary to learn the formula for calculating the standard deviation, there may be times when you wish to include it in a report or dissertation. The standard deviation of an entire population is known as Ï (sigma) and is calculated using:
After 8-20 hours, the egg hatches and the fly enters the maggot stage. It begins to feed on whatever the egg was laid on, usually decomposing flesh. The maggot gorges itself with food until it is ready to enter the pupal stage, at which point the maggot travels away from the food source to a moist spot.
Incubation may last 4 to 4.5 days, but hatching usually occurs in less than 24 hours when conditions are warm and humid. Depending on temperature and the substrate upon which they are feeding, maggots usually complete development in 4 to 10 days.At the end of this period, larvae typically burrow in the upper centimeters of the soil and pupate for up to a week. Adult flies emerge from puparia and make their way to the soil surface.upa -- Blow fly pupa are encased in light brown to black puparia (the tough, hardened skins of last instar larvae). Each puparium is 9 to 10 mm long and 3 to 4 mm wide.