1915] Life History Thelia Bimaculata 149 
Prothorax brown with two pairs of short blunt bristles. Meso-and 
metathorax each uniform brown with one pair of obsolete bristles on 
median dorsal line. Abdomen brown, posterior margins of segments 
darker; eight segments distinct, first six pairs bearing double row of 
blunt spines at dorsal line, each spine with short lateral bristles and 
ending in a fine hair, last two segments faintly bristled; anal tube 
prominent. Legs brown, somewhat lighter at joints. 
Third instar: 
Measurements: Length 3-5 mm.; maximum width 2—2.5 mm. 
Gray-brown mottled with dark brown; undersurface of abdomen 
lighter. Body wider and flatter in proportion than in preceding instars; 
widest in abdominal region. Pronotal horn beginning to appear on pro- 
thorax and lateral margins of meso-and metathorax beginning to lengthen 
to form wing-pads. 
Head wide, frontal tubercles prominent, front of head dark in color; 
eyes brown, facets distinct; ocelli visible; clypeus set off by distinct 
suture; beak extending to a point half-way between hind coxe and apex 
of abdomen. Prothorax with prominent tuberosity on median dorsal 
line; entire dorsal surface of prothorax swollen. Mesothorax and meta- 
thorax almost smooth above; lateral margins of each of these segments 
extended in blunt points. Each abdominal segment bearing double 
row of short, sharp spines above; two parallel rows of dark spots on 
each side of abdomen in about the position in which the lateral hairs 
appeared in the first instar; anal tube prominent and black. Legs mot- 
tled brown; femora almost black; tibie lighter at extremities; tarsi 
flavous. 
Fourth instar: 
Measurements: Length 5-7.5 mm.; maximum width 2.5-3 mm. 
Body robust; abdomen heavy; color light mottled gray. Pronotal 
process becoming porrect; prothorax overlapping mesothorax. Wing- 
pads well developed. 
Head decidedly prone; frontal tuberosities pointing directly for- 
ward; eyes light brown; ocelli prominent; clypeus well defined; beak 
reaching just beyond posterior coxeze. Prothorax well developed; anterior 
process becoming porrect; posterior margin of pronotum beginning to 
overlap mesonotum. Mesothorax and metathorax almost smooth 
above; wing-pads well formed and prominent, covering one-third of 
second abdominal segment at lateral margin. Abdomen very light in 
color with longitudinal brown fascia above, almost white below;  spir- 
acles very distinct; anal tube darker than the rest of the abdomen and 
often much distended; first two abdominal segments almost smooth 
above, next five bearing short, thickened spines. Legs and feet mottled 
brown, sparingly spined and pilose; femora hairy and club-shaped; 
tibiz somewhat flattened; tarsi comparatively large; claws heavy 
and strong. 
