Embryogenesis of a H. castaneus clutch at 20 ± 2 °C. A Egg mass 4 cm above water level 6h following oviposition B 5d following oviposition C 6d following oviposition D 7d following oviposition; two hatchlings of the upper egg mass and undeveloped eggs within water. For further details see text. Photos by M. Dehling.