304 ECONOMIC ENTOMOLOGY 



Adults. — Robust, pale reddish, or yellowish-brown to piceous lamel- 

 licorn beetles, with long dense hairs on the sternum; about ^ inch long. 

 On emerging from the ground they fly about at night in search of food, 

 pair in the trees and retreat again to the earth by day and remain in 

 hiding. Food plants various. 



Eggs. — Oblong-oval, pearly white, translucent; about ^--g inch long; 

 deposited singly from i to 8 inches below the surface of the soil within 

 oval cavities in the centre of balls of earth. Hatch in about 2 weeks. 



Larv(E. — -Large, soft, white grubs with brownish heads; hinder 

 portion of body thick and smooth; ventral surface of anal segment with 

 a triangular patch of brownish hooked hairs and with a median double 

 row of coarse hairs; anal slit in the form of an obtuse angle. 



PupcB. — Whitish bodies in oval cells. 



Life-history. — The eggs are laid in May and June; the grubs feed 

 throughout the next two seasons and in June or July of the third year 

 they change to pupae. Two or three weeks later they change to adult 

 beetles but remain in their pupal cells until the following spring. In 

 other words, larvae hatched in June, 1913 change to pupae in July, 1915, 

 and the beetles emerge in May and June, 1916. During the winter the 

 grubs descend for protection. The life-cycle of L. tristis is 2 years; 

 longer for all forms in the North than in the South. Not known to 

 breed in manure. 



Control. — Fall plowing; utilizing hogs and poultry; rotation of 

 crops; collecting the grubs and beetles; spraying trees upon which 

 beetles feed (see Part IV). 



Of related genera Ligyrus gibbosus, L. relictus, Cyclocephala immacu- 

 lata, Allorhina nitida, and Euphoria have a i-year life-cycle, while 

 Cotalpa lanigera and Polyphylla require 4 or 5 years. Cotalpa 

 lanigera is in some districts destructive to raspberry, strawberry, corn 

 and grass. 



Natural Enemies. — Pyrgota undata, Tiphia, Asilids, carabids; crows 

 and blackbirds; annelids; skunks, Cordyceps. 



Biological facts of importance have been obtained in recent years 

 (see Bull. 116, 186, 187, 111. Agr. Exp. Station, and Farmers' Bull. 54.3, 

 U. S. Dept. Agric.) regarding the habits of White Grubs. These may 

 be summarized as follows: 



(a) Some species, L. tristis and L farcta have a life-cycle of 2 years, but most 

 others have a cycle of 3 or 4 years. 



