Evolution and Taxonomy 



85 



apart than now. As the consolidation of the thoracic seg- 

 ments advanced, the wings were brought nearer and nearer 

 together, till finall}- the development of a connecting organ 

 was rendered possible. 



Such an organ might be borne by the fore wings, or it 

 might be borne b}' the hind wings. In some moths the spe- 

 cialization took the former direction ; in others, the latter ; 

 and thus arose a division of the order. 



This division I consider of subordinal value ; and I have al- 

 ready proposed the names 

 Jugat(z and Frenatce for the 

 suborders thus indicated.^ 



lyCt us try to obtain an 

 idea of the ways in which 

 the jugum and the frenu- 

 lum were developed. As 

 to the jugum I have but 

 little to offer beyond the 

 suggestion that at first it 

 may have been merely an 

 adventitious lobe, or a 

 slight sinuosity in the in- 

 ner margin of the fore 

 wing. If such a lobe 

 should project beneath the 

 hind wing ever so little it 

 would tend to insure the 

 synchronous action of the 

 two wings, and thus offer 

 an opportunity for natural 

 selection to act. 



The frenulum is a much more complicated organ. As a 

 rule we find that in the female it consists of several bristles, 

 while in the male it consists of a single, strong spine. If one 

 of the bri.stles of the compound frenulum of the female be ex- 

 amined it will be found to be hollow, containing a single cav- 

 ity. But when the frenulum of a male is examined it is found 



Fig. 29. — Clisiocanipa. 



Proc Am. Ass, Adv. Sci., Vol. XLI (1892), p. 200, 



