698 



THE PANORPOID COMPLEX, 111., 



van der Weele imagined, but is correlated with the increase in 

 the number of pectinate branches of Rs. 



We are now able to construct our Archetype, of which we have 

 figured the forewing only, in Text-fig. 108. The characters 

 which mark this type may be briefly stated as follows: — 



(1) Sc and Rj distinct, not fused distally, and a complete 

 series of costal veinlets present. 



(2) Rs with more than four original branches, and with a 

 tendency towards a pectinate arrangement of these branches in 



R 



2+3 



onlv 



Text-Fig. 108. 

 Forewing of the Archetype of the Order Megaloptera. Cross-veins 

 omitted, except only those between Sc and R\ and between Ri and 

 Es, which are constant. Lettering as on p. 535. 



(3) Cubito-median Y-vein reduced, with M 5 weakly formed 

 and failing to make a strong union with Cuj in forewing; in 

 hindwing, this Y-vein is fairly normal. 



(4) M x _ 4 with only four branches, dichotomically arranged. 



(5) Cu three-branched, Cuj being distally forked, as in Para- 

 mecoptera, Triehoptera and Lepidoptera. 



(6) No fusion of 1A with Cu 2 in hindwing, but these two 

 veins approach close to one another in both wings. 



(7) Cross- vein system rather irregular, widely spaced, not very 

 numerous; only three cross-veins between R x and Rs. 



In constructing the above Archetype, I have not brought 

 into consideration the two known Lower Triassic fossil genera 

 which are supposed to belong to this Order. These are Chau- 

 liodites Heer and Triadosialis Heer. The former does not seem 

 to me to be definitely Megalopterous ; the latter is very probably 

 a somewhat reduced Corydalid type, and falls well within the 



