BY R. J. TILLVAHD. 293 



From the above evidence, we iinist presume tliat the Archetype 

 of the Megaloptera possessed a somewhat reduced coupHiig-appa- 

 ratus, ill which the two lobes were present, the jugal bristles 

 absent, and the frenular bristles probably (piite vestigial. 



Order TRICHOPTERA. (Text-figs. 8-9). 



In this Order, the original wing-coupling apparatus undergoes 

 some remarkable developments, which have attracted very little 

 notice from entomologists, so far. In all the oldest families, one 

 can only recognise the jugal lobe, which is the anal lobe, of sys- 

 tematists in this Order. This appears as a strongly projecting 

 lobe at the base of the forewing, in such genera as EhyacophUa 

 (Text-fig. 8, J/). There are neither jugal bristles nor frenulum; 

 and the humeral lobe is suppressed, or else only slightly developed. 



In no case does this jugal lobe pass under the hindwing during 

 flight; it merely rests upon the costa from above. 



In the great majority of genera, the jugal lobe is absent or 

 vestigial, and new elements of wing-coup- ''**it5j— __^^<<^ 

 ling have made their appearance. This \ - ; 7 ^^.,^. 

 iieAv type of wing-coupling is awy^/e-t^/orz/i, i[-A;'',' y^ 

 i.e., it is brought about by an overfold of ^..^""^^ "" 



the whole length of the anal area of the *" ~~" 



fore wing upon the costa of the hind. But 

 besides this, there are many cases in Text-tig. 8.* 



which the amplexiform coupling is strengthened by one of two 

 new devices, as follows: — 



(1) Between the anal vein of the fore wing, and the anal border, 

 there may be developed a single row of stiii" hairs, all pointing 

 forwards and outwards, on the underside of the wing. The row^ 

 of hairs upon the costal margin of the hindwing is also stiliened; 

 so that, during flight, further strengtli is given to the amplexi- 

 form coupling by the intermingling of these two sets of stiif 

 hairs. I have seen this type of coupling in an archaic Austra- 

 lian genus of tlie family Fhryyaiteidce, not yet named. 



* Wing-coupling apparatus in Rhyacopltila dorsal U Pict., viewed from 

 above; ( x 12) : jl, jugal lobe. 



