4 BULLETIN 535, U. S. DEPARTMENT OF AGRICULTURE. 
THE EGG. 
The egg (fig. 3) is oval, capsule-like, deep orange in color, with no 
special characteristic marking or reticulations visible under a 4-milli- 
meter objective. The following are the measurements taken from 22 
egos: Maximum, 0.47 mm. by 0.84 mm.; minimum, 0.26 mm. by 0.43 
mm.; average, 0.33 mm. by 0.57 mm. 
THE LARVA. 
The immature larva.—The larva, just after 
hatching from the egg, is about 1.8 mm. long by 
0.2 mm. wide; the color of the entire body is 
rie. 3—The horse.  WHitish, the head, thoracic plates, and anal plate 
radish fiea-beetle: varying from whitish to pale brown. Within a 
ee eee few hours the head, thoracic plate, and anal plate 
become darker, and a day or more later turn deep 
brown. In other major respects, excepting the numerous transverse 
wrinkles and the relative proximity of the sete, the young larva is 
very similar to the older larva. 
The mature larva.—The larva (fig. 4), when full grown, is slender 
subeylindrical, paie yellowish white, with dark brewn head, thoracic 
plate, and anal plate; mandibles 
distinctly quadridentate; head 
with the usual V-shaped epicranial 
suture and dark median line caused 
by attachment of tentorium; five 
sete on epicranium each side of 
median line, several sete distrib- 
uted irregularly about lateral mar- Set 
. . = =) 
gins of head as shown in figure 4; 24 
£03 
thoracic plates divided by distinct 
suture; row of three sete along an- 
terior lateral margin of each plate; 
one on lateral posterior angle; four 
minute setze on posterior inner mar- 
gin of each plate; one seta on inner 
anterior angle; mesothorax with 
pale chitinous plates bearing sete, 
Rat 
Fig. 4.—The horse-radish flea- beetle: 
two 1n anterior row, four in pos- Larva; at left, dorsal view; at right, 
terior row, four on slightly elevated lateral view? Tabet ss aye uaues 
ae SE liferous hairs more prominent than in 
pleural area; metathorax similar. isan Gigeeenwunceners fue 
The thoracic legs each bear one larged.) (Original.) 
claw. 
The abdominal segments bear dorsally three rows of slightly ele- 
vated chitinous plates, each of which gives rise (when not continu- 
ous) to a seta; the first row comprises six, the middle row two, the 
ee 
