Moutli-jxirls ill a Species of Polyphix-. 



250 



(see fi^. 2). A curious "duct" (or cliitiiious clionl), cross- 

 haried like :i tiaclu'a, runs forward tVoni lictwct'ii tlio aiitorinr 

 coniua of the sclcrite iinJ bifurcates in front, cacli hruncli 

 ruiming into a basal piece or '' gland," which is, according to 

 Arnu'iiaule, only a hard flat oval piece of chitin, without 

 glandular structure. 



Vh 



\ 



Diajjcrammatic sketch of the cesopliafroal sclerite (or lyrifonu oryiui) aud 

 "<,'lands" (or basal pieces) in Mallopbaga. 



G = Gland; S = Sclerite. 



The infra-buccal plate in P. hracliyrhynchus is apparently 

 fused at least in part with the lower wall of the head. It is 

 exfreiutdy minute and correspondingly difficult to dissect, as 

 the whole head itself in this species measures only '^O ot a 

 millimetre in len<rth. The vestigial character of this plate 

 and the two chitinous chords, which arise from between 

 the two anterior horns by separate roots, is indicated by the 

 delicacy and, in different specimens, by the varying outline 

 of the parts. Hoth plate and chords are present in all 

 specimens, however, and the former stains deeply with acid 

 fuchsin. On one side in the spccinuMi from which the 

 drawing is made indications of a "gland "or basal piece 

 were observed, and its outline is therefore given. 



An infra-buccal |>late is present in other species of Poft/pla.r, 

 including I\ .yi'nuloaa. 



