140 ON THE MOUTH-PARTS OF THE MALLOPHAGA. 



lobes of the first maxillae, the maxillulse being the glands and 

 rami (or the lateral pieces as the case may be). This view- 

 has been actually put forward on behalf of the "glands" by 

 Dr. Gunther Enderlein (1903) (11). 



Conclusion. 



Dissections of the head, particularly in those species of the 

 large genus Menopon where the hypopharynx has been reported 

 to be absent, ought to yield useful data for systematic work. It 

 is curious that the case of Dochophorits sphenophorus from which, 

 at first, the glands and sclerite appeared to be absent, should on 

 careful examination be found to present a hypopharynx con- 

 stituting so abrupt a deviation fi'om the noi-mal form in the 

 Ischnocera, because this species is a typical Dochophorus differing 

 in external character but little from the group to which it 

 belongs. ISTow that schemes of classification, instead of being 

 merely arbitrary modes of arrangement for the convenience of 

 systematists, are expected to indicate phylogenetic relationships 

 whenever possible, it becomes necessary to include in descriptive 

 work internal as well as external characters. If the hypopharynx 

 were an external chai-acter, its peculiar form in D. sp)henophorus 

 would, with some students of the order, be sufficient reason for 

 instituting a new genus for its reception. 



The oesophageal sclerite is pi^obably present in all Mallophaga, 

 and in breaking up many of the unwieldy genera such as Docho- 

 phoriijS and Menopon, it should prove to be of great assistance. 

 Of the list of species of Menopon in which Snodgrass discovered 

 no sclerite present, one, M. tridens, has already been separated 

 out as Pseudomenopion tridens, and another, M. titan, as Tetro- 

 phtahnus titan. Both these new genera are now found to possess 

 an oesophageal sclerite, though in a modified form. These facts 

 are suggestive. 



Literature. 



(1) Shipley, A. E. — Ectoparasites of the Red Grouse. P. Z. S. 



1909, pp. 310-320. 



(2) NiTzscH, C, L. — Der Familien und Gattungen der Thierin- 



sekten (Insecta epizoica) als Prodromus einer Natur- 

 geschichte derselben. Germar's und Zincken's Magazin 

 fiir die Entomologie, Bd. iii. 1818, Halle. 



(3) Grosse, Franz. — Beitrage zur Kenntniss der Mallophaga. 



Zeitschr. Wissensch. Zool. 1885, xlii. pp. 536-540. 



(4) Snodgrass, R. E., in Kellogg's "New Mallophaga, II." 



Proc. Calif. Acad. Sci. ser. 2, vi. 1896, pp. 434-457. 

 (6) Snodgrass, R. E. — A Revision of the Mouth-parts of the 



Corrodentia and the Mallophaga. Trans. Amer. Ent. Soc, 



1905, pp. 297-305. 

 (6) "VVaterhouse, C. O. — Mouth of Lcpmohothrium titan. Ent. 



Soc. of London, 1904, Proc. pp. 5-6. 



