BULLETIN 436. U. S. DEPARTMENT OF AGRICULTURE. 
exceedingly limited numbers in the southwestern United States, but 
the farmer need not be concerned in regard to this, for the insects are 
quite similar in habits and methods of control. 
The adults of Cliaetocnema ectypa (fig. 1) are 
shining black, less than 2 millimeters (three thirty- 
seconds of an inch) in length, and nearly as broad 
as long. Upon a corn leaf they appear as tiny, 
nearly round objects, each about the size of the 
point of a lead pencil. The species was origi- 
nally described by Dr. George H. Horn in 1899. 
His description is necessarily incomplete, since he 
merely points out the difference existing between 
Cliaetocnema ectypa and Cliaetoenema obesula Lee, 
which it very closely resembles. The description 
flea-beetle: Egg. follows: 
Greatly enlarged. 
(Original.) Surface distinctly aeneous. Antennae rufotestaceous at 
base, the five outer joints piceous. Thorax distinctly alutaceous. The punctation 
extremely fine, indistinct, and sparse. The basal marginal line consists of fine, closely 
placed punctures. Anterior and middle femora brown, the posterior femora piceous, 
tibise and tarsi rufotestaceous. Length, 0.06 inch: 1.5 mm. 
THE EGG. 
The eggs (fig. 2) are minute, averaging about 0.35 mm. long by 
0.15 mm. in diameter, whitish and invisible to the unaided eye 
unless placed upon a suitable dark or black background. They are 
bean shaped, with one side slightly concave and one end smaller 
than the other. The surface is sculptured and of a creamy white 
luster, which becomes apparent when the egg is examined with a 
binocular microscope. 
THE LARVA. 
The larvae (fig. 3) of this flea-beetle are elongate and quite small in 
diameter; compared to the adult, they seem to be the young of a 
larger insect. When 
newly hatched they 
are very small and deli- 
cate, being less than 
a millimeter in length ; 
the measurements 
of six specimens giv- 
ing 0.80 mm., 0.75 
mm., 0.70 mm., 0.75 
mm., 0.80 mm., and 
1.10 mm., they being eight times as long as their greatest diam- 
eter. The head plate measures 0.1 mm. in width. They are pale 
white excepting the head, which is a very light straw color, and are 
Fig. 3.— The desert corn flea-beetle: Larva; a, anal segment, dorsal 
view; b, same, lateral view. Greatly enlarged. (Original.) 
