EXPLANATION OF REFERENCE LETTERS 
External Organs. 
<i Labrum-epiplmrynx. 
a x Ventral ridge of labruni 
bearing sensory hairs. 
<i* Lateral ventral hairs to 
labruni. 
a a Apical scales to labruni. 
</' Dorsal hairs to labrum. 
b Hypopharynx. 
c Labium. 
c 1 Labella. 
c* Ventral flange or lip of labella. 
t :1 Epidermis of labella. 
c‘ hirst dorsal groove in epi¬ 
dermis of labella. 
c b Second dorsal groove in epi¬ 
dermis of labella. 
c° Third dorsal groove in epi¬ 
dermis of labella (produced 
in eversion). 
i 7 Ventral groove in epidermis 
of labella. 
c H Fold forming cul-de-sac. 
c® Fold behind fork. 
d Ventral external hairs. 
d x Dorsal external hairs. 
d 1 Lateral group of external 
hairs. 
c Fork. 
c x Lateral sclerite to fork. 
/ Ventral sclerites. 
J x Hairs at apex of ventral 
sclerites. 
Palpi. 
Apodeme of labrum. 
Internal Organs. 
i —Tracheal sac. 
t 1 — Tracheal tube. 
j The teeth. 
j 1 —Accessory tooth. 
k -Tooth plate. 
/ —Petiolated blades. 
m Rod-like hairs. 
n Operculate hairs. 
o Bifurcated hairs. 
p Anterior fringe of hairs. 
p x Proximal fringe of hairs. 
(j The axial apophysis. 
r -Dorsal hooked sclerites form 
ing upper portion of the 
labial gutter. 
r 1 Sclerite forming base of labial 
gutter. 
s —Tendon. 
s 1 Dorso-ventral muscles. 
s a —Median oblique muscles. 
s 8 Ventral oblique muscles. 
i 4 Transverse muscles in cavity 
of labrum. 
s 6 Internal lamina. 
t Chitin cells. 
u —Interlocking spines. 
S 
h 
