30 
ON THE COMMON WHITE GRUBS. 
(Lachnosterna and Cyclocephala.) 
(Plate IY.) 
Order Coleoptera. Family Scarab,eid,e. 
The white grubs or “grub worms” are among the immemo 
rial enemies of agriculture in both worlds, but in neither Europ 
nor America has the problem presented by their injuries on th 
farm and in the fruit and vegetable garden received a satisfac 
tory solution. In fact, in this country the very conditions c 
the"problem have hitherto scarcely been ascertained, since, nol 
withstanding the prominence of these insects in American fan; 
economy for more than a century, their life history ha 
never yet been fully and correctly determined. The steady ir 
crease of their numbers in this State, apparently connected wit 
the gradual enlargement of the area laid down in grass, ha 
made systematic investigation of their life history, habits, an 
economic relations simply imperative and indispensable; and 
have here to report the first result of studies of our species 1 
Illinois. 
Our common and destructive white grubs all belong to tb 
genera Lachnosterna and Cyclocephala, by far the greatei nuni 
bar of both species and individuals to the former genus; but a 
the latter is also sometimes locally destructive, and as tl 
species of this genus differ in life histo.ry from those of Lac I 
nosterna in a way to affect somewhat their economic relation 
means of distinction between these groups of white grubs a 
desirable. Fortunately, distinctive characters are easily ma< 
out, and an}" one able to recognize the common grains or frui 
need not doubt his ability to tell these two most importai 
kinds of white grubs apart. 
The required distinctions are to be found at the hinder end 
the body. In Cyclocephala the under side of the last segmeij 
is thickly set with short stiff brown hairs, which are similar ail 
uniformly distributed; while in Lachnosterna the middle 
this patch of hairs is occupied with a double row 
strong blunt spines, which run in a direction lengthwise 
the bodv and leave between them a little strip or a^en 
of smooth skin. The difference between the spines of these rov 
and the other hairs of this surface is seen at a glance. Fui the 
in Lachnosterna the vent or anus, at the extreme end of t 
