WALKING-STICKS AND WALKING-LEAVES. 79 



from the carboniferous beds. Both he and Scudder 

 have treated these fossils as forming a distinct family 

 called Protophasmidae. So far as we know them, these 

 early types differed from those of to-day by being 

 invariably winged, and in that both pairs of wings 

 were adapted for flight ; the front pair what we now 

 call wing-covers, or tegmina being not leathery and 

 thickened, as now, serving as mere protective flaps to 

 the closed hinder pair, but were as large and diaphanous 

 as their posterior fellows : these ancient insects explain 

 the origin of our living giants, being twenty-five to 

 fifty centimetres long, and as much as seventy in spread 

 of wing. To them have been referred, on inferential 

 grounds, a whole group of detached wings found in 

 carboniferous beds in Europe and America. They 

 further differed from modern types in having the several 

 parts of the thorax more nearly equal in length 

 similar, in fact, to the condition while still in the egg 

 of walking-sticks of to-day ; thus illustrating once more, 

 what many naturalists believe, that in the development 

 of the individual we may trace, more or less completely, 

 the ancestral development of the race. 



The Phasmidae are a singularly isolated group ; we 

 discover no transition properly so called between this 

 family and others. So far as appearance goes, they 

 approach most closely the mantidae ; their forms are 

 sometimes very much alike ; in several mantids 



