Moiilh-parts ill a Species o/' Polyplax. 257 



Tetrophthalmus titan (Piaget), which is found firmly att.-iched 

 by means of its powerful tridentate mandibles to tlie skin of 

 the Pelican's pouch, lives on blood ; a transition from hair- 

 and feather-feeding- to gnawing at the epidermis of the skin 

 is easily conceived, when, as soon as blood is extravasated, 

 it becomes a comparatively short jump for the imagination 

 to figure how a complete change in feeding-habits came 

 about. 



In regard to the moutii- parts of the Anoplura with which 

 this note more particularly deals, it was almost to be 

 expected tliat a careful searcli would reveal traces of their 

 mandibulate ancestry. Enderlein, already in 1904 "^j likened 

 two lateral pieces within the proboscis of Hcematopinns suis 

 (L.), Leach (from the Pig), to the mandibles of Corixa, a 

 Heteropterous bug. Enderlein regards the Anopliira as a 

 suborder of the Khynchota. But the pieces in tlie proboscis 

 of Aictophthirus tricheci, Boh., described and figured by 

 JMjoberg m the paper already named bear a direct resemblance 

 to tlie mandibles of Mallophaga rather than to those of 

 Corixa, which are remarkable in form and have a peculiar 

 basal piece. Moreovei-, in a species of Pohjplax from an 

 Egyptian host — Acoivya cahirinus, Des., — about to be 

 described under the name P. oxyrhynchus, there are two 

 chitinous structures lying together behind the pharynx 

 {larynx of Enderlein), which are quite probably man- 

 dibles, and closely resemble those figured by Mjoberg, 

 i. e. each lies with its narrow end pointing inwards and a 

 teiidor.-like strip of chitin runs back from the base cf the 

 posterior lateral angle. The mouth-parts of the louse form, 

 of course, an almost classical problem in morphology, and 

 many authors, from Svvammerdam to Schiodte and after, 

 have tackled it with varying success. The inherent difficul- 

 ties in dissecting the proboscis probably constitute the reason 

 why we still lack any very settled views on its structure and 

 morphology, and the suggestions put forward here arc there- 

 fore to be regarded as the advertisement of problems to be 

 solved rather than as definite solutions. 



In another species — to be called Poly pax hrachyrhyncJius — ■ 

 from the same host, a still more interesting structure was 

 found on the under surface of the head in front of the pharynx 

 and just behind tlie mouth-opening. 



A glance at fig, 1 (p. 258) is sufiicient to suggest at once 

 to a student of the Mallophaga the well-known oesophageal 

 selerite and " glands ^' which form a prominent feature in the 



* Zool. Auz., Bd. xxviii. 1904. pp. 121-147. 



