342 Grosse’s Classification and Structure of the Bird-lice. (April, 
somewhat uniform, the occipital angles being rounded off. The 
hinder limit of the clypeus 
shows on each side a 
notch, about a third from 
the front of the head; two 
dark spots are seen on 
each side of the head, the 
larger one near the notch, 
the other behind it and 
outwards. The antenne 
lie concealed in a lateral 
cavity of the under side 
of the head (as in Læmo- 
bothrium, Fig. 1 aż). Two 
eyes, whose pigment is 
1.\—Ventral view of head of Lemo. Seen from above, lie on 
bothtiam from Gypogeranus serpentarius. X30, each side below and be- 
hind the antennal cavity. Hairs are distributed over the head, 
along the borders and on its ventral and dorsal surfaces. On tke 
under side of the head is the funnel-shaped 
mouth-opening, surrounded by the mandib- 
ulate mouth-parts. Grosse describes the 
mouth-parts of Mallophaga in detail, as 
previous writers err greatly regarding them. 
Labrum (oberlippe)—This is not, as in 
other insects, inserted on the anterior bor- 
der of the head, but in all Mallophaga it is 
ch 
Fig. 2. Fig. 3. 
Fic. 2.—Media ction through head of G: a ae y- 
Labrum of Comins d dissimilis. st bo. mt Denies acne. X 
1 Explanation of acta letters in the figures.—at, ennz ; ch, chitinous bar; 
ds, vs, dorsal and v corres of cesophageal sala: g, glossa (ligula); r ? 
5 glassy , hypop x; is, os, inner and outer side 
- illa; Z,lens-shaped iisi thickening; 2, labrum (upper lip) ; md, r.md, left and 
_ right mandible ; %, labial palp; m, muscle; md, mandible; m¢, mentum; mx, ist 
- re e mx’, ad maxilla (labium or under lip) ; oc, eyes ; ozs, esophagus; 0%, optic 
nerve; J, paraglossa ; v, retinal cells. 
