260 



Mil. B. F. CUMM1NGS ON 



antennae, and across the base of the head there appears to be a 

 commissure, although it is impossible to be sure that this does 

 not consist of two separate branches. I find similarly an 

 apparent commissure between the two lateral trunks, in exactly 

 the same position, in the head of Polyplax spinulosa. Polyplax 

 spinulosa further resembles P. oxyrrhynchus in the presence of 

 a large anterior root on each lateral diverticulum in segment 4, 

 which runs forward through the next segment. 



Measurements of Polyplax oxyrrhynchus [in millimetres). 



$. 



Lena-tli of antenna '15 



¥• 

 •15 



Metamorphosis. — Very little mention of the post-embryonic 

 changes of either Anoplura or Mallcphaga is to be found in the 

 rapidly growing literature of these two groups. In Warburton's 

 (10) Report to the Local Government Board an account, in some 

 detail, is given of the life-cycle of Pediculus vestimenti, while 

 Dr. A. C. Oudemans (11) has described the nymphal stages of 

 three species of Mallophaga — Lioiheum flavescens, Philopterus 

 celebrachys, and P. macrocephalus. Patton and Cragg (5) figure 

 the three larval stages of Pediculus vestimenti ; while in the 

 standard work ' Les Pediculines ' (p. 6) Piaget (2) makes a few 



