new mallophaga. 44i 



The Mouth-Parts of L^mobothrium sp. 



(Plate lxi, figs. 1-5.) 



The labium of Lc&mobothriuni sp. (plate lxi, figs, i and 

 4) consists of submentum, mentum, palpi, and ligula. 

 The labium as a whole occupies two-thirds of the length 

 of the ventral surface of the head. Its anterior border 

 lies in front of the bases of the antennae, and extends also 

 considerably farther forward than the bases of the man- 

 dibles ; hence the latter are almost concealed by the la- 

 bium. 



The submentum (plate lxi, fig. 4, 5;;/.) is a transversely 

 narrowed sclerite very convexly rounded posteriorly, and 

 slightly concavely rounded laterally where it joins the 

 temporal sclerites. The anterior border is more decided- 

 ly concave and articulates with the convex posterior bor- 

 der of the mentum. The submentum is a little wider than 

 half its length, and on the whole is somewhat narrowly 

 shield-shaped. In front of the submentum is the men- 

 tum (plate lxi, fig. 4, ;;/). This sclerite is wider than 

 long and is somewhat oval in outline, with the long 

 axis transverse; the latter is a little in front of the 

 middle point. The lateral and posterior borders are 

 very convex, and the sclerite may also be regarded as 

 being an isosceles triangle with the angles very much 

 rounded, and the apex pointing backward. Laterally there 

 are two short thick, anterior prolongations, ff, one on 

 each side. These bear the short four-jointed labial palpi. 

 Each segment of the palpus is rather short and cylindrical 

 and bears a few hairs. The terminal one is shorter than 

 the others and forms a rounded termination to the palpus. 

 The ventral surface of the mentum is produced downward 

 into a large saccular or pouchlike distention which is 

 almost as wide and long through its greatest diameters as 



Proc. Cal. Acad. Sci., 2d Ser., Vol. VI. ( 31 ) November 9, 18'JG. 



