296 THE PANORPOID COMPLEX, 1., 



he claims to be intermediate between the other two. These 

 families together form the 8uborder Jiigatfp* of Comstock, or the 

 group Micropterygina of Meyrick. The latter author (3, p. 7 97) 

 thus defines the character of the wing-coupling apparatus in this 

 group:— "Fore wings with an oblique membranous dorsal process 

 ( jugum) near base, forming with the dorsal margin a notch or 

 sinus, which receives the costa of the hindwings. Hindwings 

 without frenulum." 



This may be taken as a standard definition of the jug<ife type 

 of wing-coupling; provided that we add what is perhaps not 

 quite apparent at first sight, that this true jugum passes under 

 the costa of the hindwing, and so forms the notch or sinus above- 

 mentioned, in which the costa is held as in a finger-and -thumb 

 grip. The nature of this coupling-apparatus is best understood 

 by ref ei-ring to Text-fig. 1 1 . 



As contrasted with this J>'[/"-fe type, the rest of the Order is 

 usually regarded as forming a single Suborder Frenatae,"^ in which 

 the majority of the families possess a frenulum, but no jugum. A 

 good definition of this character has been given by Meyrick (3, 

 p. 4): — "Generally from or near the base of the costa of the hind- 

 wing rises a stiff bristle or group of bristly hairs, termed the 

 freiinlfon, of which the apex passes under a chitinous catch on 

 the lower surface of the forewing, termed the retinaculum^ thus 

 serving to lock the wings together; the frenulum is commonly 

 single and strong in the male, multiple and weak in the female; 

 the retinaculum in the female is commonly represented by a 

 group of stiff scales." 



However, certain families of the Frenata, including the great 

 division Rhopalocera or Butterfiies, do not possess this frenulum. 

 In these forms, the coupling of the wings in fiight is brought 

 al^out by the downward pressure of the posterior margin or 

 dorsum of the forewing upon the costa of the hind, the latter, on 

 its part, pressing strongly upwards from beneath. The humeral 



* I fail to understand the use of the feminine plural, since tliese w'ords 

 are adjectives, and should agree with the neuter phual noun Ltpidoptera. 

 I propose, therefore, in future, to write them Jngata and Frenata, respect- 

 ivelj-. 



