ORIGIN OF LEPtDOPTERA. 5 



the fore- and hind-wings together by a juguni, such as exists in the 

 Hepialids and Micropterygids, is the same as obtains in many of the 

 Trichoptera. He further found, in a study of the scales of the Lepi- 

 doptera, that, in addition to the ordinary specialised lepidopterous 

 scales, there was, on the wings of the MICROPTERYGIDES and HEPIALIDES, 

 a covering of very fine hairs, differing radically from the scales in size, 

 arrangement, and mode of attachment to the membrane, and he con- 

 siders that these hairs are practically identical with the clothing of the 

 wings of the Trichoptera, only that they are in a more generalised 

 state. On the other hand, he finds on the wings of the Trichoptera, 

 in addition to the fixed unstriated hairs, a sparse covering of specialised 

 hairs, striated, set in sockets, and easily rubbed off, which he looks 

 upon as the lepidopterous scale in a generalised state. He concludes 

 that the stem-form of the Lepidoptera possessed a wing-clothing very 

 much like that now exhibited by the Trichoptera. 



In another paperf , Kellogg shows that the mouth-parts of the Trich- 

 optera bear considerable affinity with those of Lepidoptera. He says 

 that "the maxillae and labium in general characters are similar in the 

 two groups," whilst " the matter of the mandibles is of special interest. 

 In certain species of Micropteryx (i.e., in the Eriocephalids) they are 

 present as functional organs, although the tendency towards their 

 reduction is fully displayed within the limits of the genus. In 

 Trichoptera, functional mandibles have not yet been found, although 

 the distinct rudiments of mandibles are present. Manifestly now, as 

 the tendency of specialisation in both groups is towards a reduction to 

 complete atrophy of the mandibles, the JUGATE cannot be looked 

 upon as in any way lineal descendants of the Trichoptera. The 

 affinity of the two groups must be of the character of two dichoto- 

 mously divided lines of descent, diverging from a racial type, which 

 possessed conditions of mouth-parts, wing-neuration, wing-clothing 

 and thoracic structure, of a character suggested by the present con- 

 ditions of the organs presented by the generalised members of the 

 two groups." 



Still another paper! by this author throws considerable light on 

 the subject under discussion. By the comparison of the lepidopterous 

 neuration, as exhibited in Micropteryx and Hepialus, with that of the 

 Trichoptera as exhibited by Neuronia, as also with that of Panorpa, 

 he shows that the similarity of the neuration is very considerable, 

 and states that, on the fore- wings of all, " the simple unbranched 

 subcostal (nervure), the five-branched radius, the persisting stem of 

 media coalescing at its base with cubitus, the three branches of media, 

 and the reduced anal field, are common characters. In the hind-wings, 

 the general character of the neurational uniformity is only varied by 

 differences which, in themselves, are additional evidences of a com- 

 munity of plan." It is impossible here to discuss this particular 

 phase any further, and we can only state the author's conclusion, that 

 the Xrichopterous and Lepidopterous wings "may have had a 

 generalised prototype very like the Mecopterous wing." 



Meyrick also refers to the close similarity existing between the 



* The Taxonomic value of the scales in the LepidopteYa, pp. 45-89. 

 t"The mouth-parts of Lepidoptera," American Naturalist, 1895, p. 54t6etseq. 

 t "The affinities of the lepidopteroua wing," American Naturalist, 1896, p. 709 

 et seq. 



