between five and seven and a half centimeter
one flight annually
best on Robinia (or other woody Fabaceae). Alternatively Quercus robur (or other white oaks) and Fagus
Not difficult, but a minimum of experience is required. Keep them in well ventilated plastic containers (you will not be able to keep the Robinia fresh enough otherwise), avoid condensation (or any other form of wetness) and keep the temperature moderate (somewhere between 20 and 25° Celsius). Higher temperatures are tolerated as long as there is a good cooling of at night. Fast growing and ready to pupate in five to six weeks. Most of the pupae will overwinter in a cool (but frost free) room. Still, keep an eye on them. When the conditions are right some might decide to hatch anyway in autumn. This may also happen very early in the next year when temperatures are going up for a while (moths emerging as early as February are not unusual in captivity).
avoid extremes in temperatures during summer