216 TIIK PANORPOID COMPLEX^ 



Another point of interest in the forewing is that Cm forks very far distad, 

 well beyond the level of the forking of Mi_4. This should be compared with the 

 condition to be seen in Euschemon, where the fork of Cui is placed much nearer to 

 the base; and, consequently, in the imago, Cui„ and Cuih leave the areocel much 

 further apart than they do in the Thyrididae. There can be little doubt that 

 the condition to be seen in Euschemon and in other Butterflies is the more primi- 

 tive of the two. 



In dissecting the forewing of the pupa of Morova, I looked carefully for 

 the trachea 3A, but failed to find it. This trachea is (juite easily seen in the pupal 

 wing of Euschemon. Thus there is here a third character in which the Thy- 

 rididae are more highly specialised than the oldest forms among'st the Butterflies. 



In the hindwing, trachea Ri is dominant over trachea Sc, as in the Tortricid 

 Carjjocapsa (Part 3, p. 665, Text-fig. 89) the Oecophorid Wiiiyia (Part 3, p. 660. 

 Text-fig. 90), and the Butterfly Euploea (Part 3, p. 685, Text-fig. 101), but not as 

 in Euschemon (Part 3, p. 680, Text-fig. 99), where the reverse is the ease. This 

 character is not, however, of much importance, as we do not yet know how vari- 

 able it may prove to be in the different families. Of more interest is the absence, 

 in Morova, of any sign of a humeral veinlet in the hindwing. Such a veinlet is 

 to be seen in the pupal wings of many Butterflies. 



The very strong arching up of Mi towards Rs in the hindwing of Morova ap- 

 pears to be a somewhat more specialised condition than that found in Euschemon. 



The anal area of the hindwing in Morova is of very great interest. The 

 pupal tracheation fully confirms my original interpretation of the anal veins in 

 the imago of Rhodoneura. Trachea lA is present in the pupal wing, in much the 

 same condition as in the Cossid Xlyeutes (Part 3, p. 661. Text-fig. 87), but 

 slightly more spe^'ialised by reduction, in that it fails to reach much more than 

 half-way towards the wing-border. It has, as in Xyleutes, lost its original con- 

 tact with Cu2. and makes a strong downward curve towards 2A, without actually 

 coming into contact with it. In the imago, lA and 2A l)eeome fused, thus form- 

 ing the basal anal Y-vein shown in Text-fig. 98. 



This condi.tion is much more primitive than that to be seen in the pupal 

 hindwings of Butterflies, where lA is completely absent, and consequentlj' there 

 is no basal anal Y-vein present. It would seem to indicate a close connection 

 between the Thyrididae, and the more primitive types of Heteronenra, in wliich 

 trachea lA is preserved in much the same condition. 



Trachea 3A is present in the pupal liindwing of Moroca. as in that of the 

 Butterflies, and bscomes chitinised in the imaginal venation. Trachea Cu2 is also 

 present in the pupal hindwings of both groups, but fails to become chitinised in 

 the Butterflies, tliough it is sometimes partially and very feebly indicated in the 

 imagines of Thyrididae. 



To sum up, then, there are three characters in tlie forewing of tlu' Thyriclidw, 

 which are more liighly specialised than the corresponding conditions to be lound 

 in the oldest Butterflies. The hindwing, on the other hand, is in most respects 

 more archaic than that of the Butterflies. 



We may conclude from this that, while there are obvious affinities between 

 the Thyrididae and the older groups, especially the Tortricina. and also lietween 

 the Thyrididae and the Pyralididae (thougli the [luiial wing-s of this latter family 

 still remain to be studied), yet there is no evidence that the Thyrididae stand in 

 any direct ancestral line to the Butterflies, as Meyrick and Hampson have averred. 

 There is, on the contrary, very distinct evidence, in tlie form of three clinracters 



