HARRISON. 



155 



Family Trimenoponidae. 



In my Genera and Species of Mallophaga (1916, p. 27), I established the 

 family Trimenoponidae for reception of the genera trimenopon and Philandesia, 

 without, however, giving a diagnosis. 



The Trimenoponidae may be defined as two-clawed mammal-infesting Am- 

 blyeera with a spinous ehaetotaxy ; with reduced mandibles and modification of 

 the mouth in the direction of a sucking organ; with head and thorax together 

 almost as long as the abdomen and with no niesothorax visible in the mid-dorsal 

 line; with first abdominal segment reduced, the tergite not reaching the lateral 

 margins; and with five pairs of abdominal stigmata on segments 3-7. 



As at present known, the family includes three genera, Trimenopon Cum- 

 mings, Philandesia Kellogg and Nakayama, and Acanthomenopon now described 

 as new. The species of these genera occur upon South American rodents and 

 marsupials, and it is suggested that, as they do not occur upon rodents else- 

 where, the family will really prove to be characteristic of American marsupials. 

 The family is most closely related to the Boopidae, occurring on Australian 

 marsupials, and to the Gyropidae, which are confined to South American rodents. 



Text-fig. 1. Underside of head of (a) Philandesia, (b) Trimenopon, (c) 

 Acanthomenopon. 



Key to the Genera of Trimenoponidae. 



Philandesia 



A. Lateral margin of head deeply emarginate 



AA. Lateral margin entire. 



B. With a ventral plate partly covering the antennary fossa below 



Trimenopon. 



BB. Without ventral plate, but with two broad stout spines projecting 



beneath antenna . . . Acanthomenopon. 



Genus Philandesia Kellogg and Nakayama. 



Kellogg and Nakayama (1914, pp. 198-200) give a fairly detailed descrip- 

 tion and figures of the single species included in the genus, P. townsendi, from 

 Lagidium peruanum, as well as a diagnosis of the genus. The authors' descrip- 

 tion of the mouth as "a sort of grasping tube or furrow" is not quite clear to 

 me. The furrow spokto of is on the upper surface 6f the hypopharynx, and 

 not external, as I at first took- the authors to mean. Their figure might be in- 

 terpreted either way, and give's no indication of the great development of chitin- 



