134 BRITISH LEPIDOPTERA. 



reach, when extended, to about the second third of the length of the 

 second palpal joint. Its inner edge is directly connected with the 

 inner lobe (inala interna). The latter are coalesced into a short, wide 

 tube, which, by the greater size of the hinder wall, opens exter- 

 nally on the point, also appearing as if at the same time cut off 

 obliquely from within outward. The outer exterior edge of the tube 

 forms a strongly chitinous semicircle, which, becoming thinner, finally 

 passes into the delicate membranous hinder wall. Anteriorly a deli- 

 cate membrane also appears to cover the chitinous portion. We have 

 here in opposition to the weak, naked underlip, represented by a 

 triangular chitinous plate in other Lepidoptera, a true ligula formed 

 by the coalescence of the inner lobes of the second maxilla? into a tube, 

 as in many Hymenoptera, and with free external lobes which corre- 

 spond to the paraglossas of Hymenoptera." 



With regard to a paired structure which he considers to be the 

 hypopharynx, Walter states : "A portion of the inner surface of the 

 tube-like ligula is covered by a furrow-like band which, close to the 

 inner side, is coalesced with it, and, in position, shape, as well as its 

 appendages or teeth on the edge, may be regarded as nothing else 

 than the hypopharynx." He then continues : " In the Microptery- 

 gids (Eriocephalids) the furrow is here coalesced within with the inner 

 side of the labium, and though I see in the entire structure of the 

 head the inner edge of the ligula tube extended under the epipharynx 

 as far as the mandible, I must also accept the fact that here also the 

 hypopharynx extends to the mouth-opening, as in all other sucking 

 insects with a well-developed underlip, viz., the Diptera and Hyme- 

 noptera." 



Walter further shows that the mandibles also exist in the form of 

 true gnawing jaws, like those of the biting insects. They possess 

 powerful chitinous teeth on the opposed cutting edge, twelve to fifteen 

 on each mandible and also the typical articulating hook-like processes 

 by which they are joined to the gena, and fit in corresponding cavities 

 in the latter. In Eriocrania, and other of the more generalised moths, 

 the mandibles in a very reduced form have survived as functionless 

 vestiges of the condition in Micropteryx (Eriocephala). 



Kellogg, in a paper that would have been much more useful than 

 it is, had it not been for the mixing up of the Micropterygid (Erio- 

 cephalid) and Eriocraniid species in his examination, states that in 

 M. anderschella, it appears to him to be the outer lobes of the maxillae 

 which seem to be free, while the inner ones go to form the very 

 rudimentary proboscis referred to by Walter. However, he is not at 

 all satisfied (nor clear) on the matter, and prefers to leave it open. 



As to the use to which the remarkable mouth structures of the 

 imagines may be put, Chapman says that they use their great claw-like 

 maxillary palpi with sharp knife points to scrape and tear at both the 

 pollen of the stamens and the surface of the petals, in the latter case, 

 perhaps, collecting fallen pollen. They certainly do something very 

 like eating as regards this pollen, and digest and use it, as would 

 appear from two circumstances : firstly, that very slender moths get 

 very fat, and lay many eggs, and, secondly, their dejecta are 

 very abundant. Moths will live in confinement for three weeks if 



* " The mouth-parta of the Lepidoptera," American Naturalist, 1895, pp. 546 et seq. 



