162 Inheritance and Evolution in Ortlioptera I 



In the vicinity of Chicago, the genus Tettigiclea is found to be about 

 equally divided between the long and short winged individuals. They 

 are almost strictly dimorphic. The genus Tettix exhibits polymorphism 

 in respect to this character, running all the way from extreme short to 

 extreme long wingedness. The shorter winged individuals predominate 

 in this genus, while the extreme long winged ones are rare. In the 

 genus Paratettix, Bol., under more particular consideration in this 

 paper, long wingedness is the rule in the Chicago region — only two 

 short winged individuals having been observed among many hundreds. 

 In Arkansas, a few short winged individuals were found among several 

 hundred long winged ones, while in Louisiana and Southern Texas, the 

 two forms, practically without intermediates, existed in about equal 

 proportions. In the North, in nature, only one generation a year of 

 any of the species is produced and the growth period is normally in 

 the late spring and early summer when the adult stage is reached 

 quickly, while in Louisiana and Texas Paratettix produces tw^o or three 

 generations a year, and the growth period continues practically through- 

 out the year, with the optimum in the spring and early summer. 



(2) Long and short wingedness in the breeding experiments. 



The observation on the occurrence of long and short winged forms 

 during the breeding experiments will be reported at this time only for 

 the individuals maturing in the inheritance of the colour pattern in 

 Exp. I (Table I). In that experiment the wing length of the individuals 

 was not considered just as in the following account the colour patterns 

 are not considered, there being no apparent correlation between the 

 length of the wings and the pattern. 



Referring to the diagram (diagram II), the first mating was made 

 in September 1908 between one short winged male and two short 

 winged females. At least one of the females was not virgin. Th« 

 jf^i generation which hatched in December matured after great mortality 

 the following March and April in these proportions : 



Long winged 17 : Short Winged 15 {F^). 



The short winged individuals, inbred, produced progeny which hatched 

 in May and became adult in July and August in the following ratio : 



Long Winged 224 : Short Winged 7 {F^). 



These F^ short winged individuals, inbred, produced progeny in Sep- 

 tember, which, after great mortality, matured the next March and all 

 were short winged. 



