60 



THE AMERICAN NATURALIST [Vol.LVI 



triploidy for the autosomes, others are sex-limited. 

 Within the class of intersexes there is a very wide range 

 of fluctuation, on the one hand to flies that are nearly fe- 

 male and on the other to flies that are entirely male in 

 appearance. In an intersex of a given grade the several 



characters do not all present the same intermediate step 

 l)et\vceii male and female, but, apparentlv just as m the 

 intersexes ot Lymantna, some characters are completely 

 male, some completelv female, while others are complex 

 mixtures of male and female parts. When the intersexes 

 aic classified according to a svsteni ot grades, thev are 

 seen to l)e a bimodal class consisting of more female- 

 t vpc " and more " male-tvpe " intersexes, both of which 

 fliieiiiatr \\ i(lt'l\- and oxcrlap eonsiderablv. 



In'' t(i!()nir;il I II \ est ligation ot the intersexes had 

 shown inai there are lour sub-tvpes of intersexes that 

 (litter III the presence or a])sence of a Y and m having 

 tliree or oiilv two tourth-cliromosomes. It is possible, 

 and there is some slight cvtological and genetical evi- 

 dence 111 support, that the male- and female-types of 



