346 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1950 



When the embryo has developed into a well-formed nymph within 

 the eggshell, it is ready to push through the head end of the shell and 

 wriggle toward the open air. Egg masses of Chinese and narrow- 

 winged mantids that I have collected for hatching have shown that 

 the great majority of nymphs from any one egg case appear the same 

 day, usually within an hour. A few early nymphs, perhaps as many 

 as 10, may appear a day or a few days previously, and a week later 

 occasional stragglers may still hatch, but hatching is very much a 

 dramatically sudden event. Some exceptions, mainly among tropical 

 species, have been reported. 



When the newly hatched nymph, with limp legs and antennae, 

 wriggles into the open air and, from its own weight, hangs downward, 

 it sheds its transparent skin almost at once. Following this act, 

 the legs stretch out, the body takes on an erect shape, and the little 

 nymph is soon ready to walk. This is the true first-stage nymph, and 

 the molt that has just occurred is the intermediate molt, so named by 

 Uvarov who carefully described a corresponding and fully compara- 

 ble event during the hatching of grasshoppers. The cast skins of the 

 intermediate molt, almost embryonic skins as it were, constitute the 

 membranous shreds hanging down from the hatching surface after 

 hatching has occurred. The newly emerged nymph often remains at- 

 tached to the shed skin for a short time while the body and legs are 

 hardening, and the nymph may appear to be dangling from silken 

 threads. Within a few days after hatching the effects of weathering 

 have removed these cast skins from the old egg case. 



Following the intermediate molt, the skin is shed six to nine times 

 before maturity is reached. The number of molts differs somewhat 

 in different species and is variable within the same species. At each 

 molt the size increases, and after the later molts the buds or pads 

 of developing wings become more noticeable. Most of our mantids 

 have long, fully developed wings when mature, but some are entirely 

 wingless, or have very short wings, or the wings of one sex only are 

 short or entirely lacking. Females are usually larger and more robust 

 than males. 



Although first-stage nymphs are all similarly colored, later stages 

 may show that either green or brown is dominant. Attempts have 

 been made to show that these colors are correlated with similar en- 

 vironmental backgrounds, or with weather conditions, but reliable in- 

 formation on these matters is still insufficient. 



MATING AND THE EATING OF MALES 



There is a widespread belief that, following mating, the male 

 mantid is always eaten by the female. This actually happens in 

 many instances, but with some of our more common species the males 

 usually escape. In some species males may notice the females and 



