156 ON THE MALLOPHAGAN FAMILY TRIMENOPONIDAE, 



ous brushes on the anterior lobes of the hypopharynx. What the authors des- 

 cribe as the mesothorax is obviously the combined meso- and metathorax; while 

 their "metathorax" really comprises the first two abdominal segments. The first 

 abdominal segment is reduced, as in both the remaining genera of the family, 

 and its hind margin is clearly indicated, without comment, in Kellogg and 

 Nakayama's figure (I.e., p. 198), but the lateral margins are not shown. These 

 curve round and run straight forward to the metathoracic border, so that the 

 tergite is narrow oblong transversely, and not crescentic as in the other two 

 genera. The ocular emargination is described and figured as if its anterior and 

 posterior borders were continuous in the same plane, but this is not the case. 

 The anterior border passes backwards and downwards under the posterior to the 

 inner limit of the antennary fossa; while the posterior border, keeping in one 

 horizontal plane, just overlaps the anterior. 



The genus may be defined as : — Trimenoponidae with a lateral emargination 

 of the head, the anterior border of which passes under the posterior to the 

 inner limit of the antennary fossa, the posterior just overlapping the anterior; 

 with a ventral plate covering about half the antennary fossa below ; with maxil- 

 lary palps long, passing the head margin ; with hypopharynx and pharyngeal 

 skeleton modified to form a rounded chamber with grooved floor; with a great 

 development of hypopharyngeal brushes; and with pads of moderate size upon 

 the basal tarsal joints. 



Genus Trimenopon Cummings. 



Cummings (1913, pp. 39-41) gives an adequate description and figures of 

 his type species, T. echinoderma (= T. jermingsi Kellogg and Paine), from 

 Cavia aperea; but his generic diagnosis is brief and insufficient. 



The genus may be defined as: — Trimenoponidae with lateral margin of head 

 entire; with a ventral plate covering about half the antennary fossa below; with 

 maxillary palps long, passing the head margin ; with mouth parts not specially 

 modified, but with weak mandibles; with a complex sculpture of the cuticle, re- 

 sembling that seen in many Gyropidae; with complex <$ genitalia; and with 

 large pads upon the basal tarsal joints. 



Genus Acanthomenopon nov. 



Trimenoponidae with lateral margin of head entire; with no ventral plate, 

 but with two large dagger-like spines projecting beneath the antenna, one from 

 the anterior, the other from the inner border of the fossa; with maxillary palps 

 short, not passing the head margin; without sculpture of cuticle; with simple d" 

 genitalia; and with small pads on the basal tarsal joints. 



Genotype: — Acanthomenopon horridum Harrison. 



Habitat: — Upon American marsupials of the genus Peramys. 



Acanthomenopon horridum n.sp. 

 (Text-figs, lc and 2.) 



Material: — 1 <S and 5 9 $ from skins of Peramys domssticus from Para; 

 and 2 <S c? and 4 ? $ from a skin of Peramys sp. (B.M. No. 3.9.5.148) from Bahia, 

 in the British Museum (Natural History). The specimens are not in good con- 

 dition, having lost many of their hairs and, in most cases, the greater part of 

 their legs, so the description, though based upon the types, is to a certain extent 

 composite, particularly with regard to the chaetotaxy. 



Description of d : Head. Almost twice as wide as long, shape best seen 

 from Fig. 2, not so triangular as in Philandesia and Trimenopon owing to pro- 

 minent bulge in frontal region; hind border slightly concave; lateral margin en- 



