PLATE 3 
Rhagoletis pomonella 
A. —Pharyngeal skeleton and associated parts, lateral view, mature larva of 
third instar. 
B. —Larval pharynx and left oral hook. Same as A with soft parts removed. 
C. —Larval pharynx and skeleton with oral hooks, diagrammatic. 
D. —Transverse section of larval pharynx and pharyngeal skeleton through 
bases of wing plates, anterior view. (Compare with C.) 
E. —Dorsal view of pharyngeal skeleton, with oral hooks and frontal sacs, 
third-instar larva. 
F. —Vertical, lengthwise section of head and first four segments of mature 
maggot, showing pharyngeal skeleton and musculature, the frontal sacs against 
the brain lobes, imaginal buds of labium and legs, ventral ganglion, salivary 
glands, and anterior parts of alimentary canal ((E, Pvent, Vent). 
EXPLANATION OF SYMBOLS 
1 , prothorax. 
2, mesothorax. 
3, metathorax. 
I, first abdominal segment. 
A, anterior lateral or triangular plate of larval pharyngeal skeleton. 
a , arms of plate A in roof of atrium. 
ab, antennal bud in frontal sac. 
Atr, atrium, anterior, part of larval pharynx resulting from involution^of 
original head of larva. 
B , posterior lateral plate of pharyngeal skeleton. 
b, ridge on plate B of pharynx. 
Br, brain. 
C, dorsal or wing plates of pharyngeal skeleton, developed in arms of dorsal 
pouch of atrium. 
c, ridge on plate C of pharyngeal skeleton. 
D , bridge plate of pharyngeal skeleton in roof of atrium. 
d, vertical, longitudinal folds of floor of pharynx. 
DiMcl, dilator muscles of pharynx. 
DP, dorsal pouch of atrium, divided beyond base into two wings containing 
plates C of pharyngeal skeleton and leading to roots of frontal sacs. 
DPMcl, dorsal protractor muscles of pharynx. 
DPhy, dorsal wall of pharynx. 
e, chitinous bridge in floor of atrium connecting pharyngeal plates A. 
EM cl, extensor muscles of oral hooks. 
/, two small sclerites in floor of pharynx just behind the mouth. 
FMcl, flexor muscle of oral hook. 
FS, frontal sacs, containing imaginal buds of antennae and compound eyes. 
*(r, pupal hypoderm separated from larval pharyngeal skeleton. (See A.) 
g , anterior sense papilla on snout of larval head. 
GC, gastric caecum. 
Gng, ventral ganglionic nerve mass. 
h, posterior sense papilla of snout of larval head. 
Hk, Hks, oral hook, oral hooks. 
L u L 2 , L 3 , leg buds of prothoracic, mesothoracic, and metathoracic legs, 
respectively. 
LbB, imaginal buds of labium. 
LH, larval head. 
LPMcl , lateral protractor muscles of pharynx. 
Mth, larval mouth. 
op, optic bud, imaginal bud of compound eye. 
(E, oesophagus. 
Phy , lumen of larval pharynx. 
Pvent, proventriculus. 
SalD, salivary duct. 
SalGl, salivary gland. 
Vent, ventriculus. 
VPhy, ventral wall of pharynx. 
