BY R. J. TILLYARD. 



289 



definite, jif{/a/ Johp ( //), from the more distal portion of whicli 

 arises a set of about a dozen small, but stiff and closely set, ji'(j<il 

 J)ristlp)< (jh), which make contact with the costa of the hindwing 

 in flight. In the hindwing, there is a small but quite definite 

 hiviupral lobe (hi), from which spring the two enormous bristles 

 of the frennl urn (fr). These latter, during fiight, joass under — 

 and, indeed, quite beyond the interior border of — the jugal lobe 

 of the fore wing. The whole apparatus is eminently suital)le for 

 maintaining contact between the two wings in flight, without in 

 any way linking the hindwing /??•;?? /y to the fore. 



In the wings of the family Xannoehorlstidiv (Text-fig. 2/>), which 

 are specialised by reduction, w^e ty. 



meet with much the same struc- il 



tures. But in this case there is a 

 single, strong, jugal bristle on the 

 forewing, instead of a set of 

 weaker bristles. The flight of q^ 



these insects is the strongest of // y\ ■■••... r-' 



any in the Order, and the wings J 



are closely linked together. The jl 



linking is accomplished by the /^ 



two sets of bristles. The frenu- 

 lum passes under the jugal lobe, 7 . f k/'"'"^^ -jb 

 while the jugal bristle passes ^' 

 above the bases of the frenular ^^^,>'-^^:^:3 ^3 L ijy'h<'^<^><K,^ f 

 bristles, and presses down upon 

 the costal area of the hindwing, 

 thus forming a very neat and 

 perfect coupling-apparatus. ^^ ' ^'" 



In the archaic J/^roy^?V/r^(Text-fig.3), there is a peculiar special- 

 isation not found anywhere else, to my knowledge, within the 

 Insecta. The jugal lobe beai-s a very distinct, black tubercle, 

 projecting from its border. This tubercle appears to have been 



* Wing-coupling apparatus in Mecoptera. a, In T<vniocliorisfa pallida 

 E.-P., wings connected, viewed from beneath. I>, In Xannochorida dipter- 

 o/ri(N Till. , wings disconnected. (Both ;< 88). Lettering as in Text-fig. 1. 



