I had wild-caught chinese mantids last year--some lived until almost Christmas, and almost all laid ooths. Most of the mantids were about 4 inches, except one was 4 1/2 inches, and one was only 3 3/8 inches. The smaller mantis did lay smaller ooths, and the bigger mantids laid quite large ooths, but decreasing in size as they laid more and more. Unfortunately, the ooth of the small mantid didn't hatch, but I'm assuming her nymphs would have been the same size as any other chinese mantis--there would just be fewer of them.