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 finally the development of a connecting organ 

 was rendered possible. 



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

 might be borne by 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 

 Jugatiz and Frenatcz for the 

 suborders thus indicated.* 



Let 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 1 o b e 

 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 opportunit}' 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 bristles 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. — CHsiQcampn, 



* Proc. Am. Ass. Adv. Sci., Vol. XLI (1892), p. 100, 



