36 BULLETIN 891, TT. S. DEPARTMENT OF AGRICULTURE. 



(Grijllotalpa borecMs Burm.) were observed, but it is questionable if 

 any of these actually feed on the larvsB. 



Macrocheles mwrginatus Herm., a mite, according to Harry B. 

 Weiss, has been found attached to the adults of this species. 



A FUNGUS PARASITE. 



Adults of this grub are often found dead and their bodies covered 

 with a fungous growth. In some instances, when a pupal cell was 

 opened, the pupa would be found dead, apparently from the effect 

 of some fungous disease. 



In rearing cages maintained by the cereal and forage crop insect 

 investigations the grubs were noted to be attacked by the green mus- 

 cardine fungus (Metarrhizium anisoplme). 



The same fungous disease was observed attacking the larvae at 

 Norfolk, Va.. during July, 1916. 14 



From what has been stated in regard to the control of this species 

 by natural enemies, the evidence is that this manner of reducing the 

 numbers of both beetles and grubs, especially the latter, is of the 

 highest importance. In the District of Columbia, and probably in 

 many other localities in similar latitudes, including portions of 

 eastern Pennsylvania, the digger-wasp, DiscoJia ditbia, has con- 

 trolled this species for several years. In other localities perhaps 

 other predators are largely instrumental in holding the pest to 

 normal numbers : and the numerous bird enemies, especially the 

 crow blackbird, are also very efficient destroyers. It has already been 

 stated that the habit of the larva of coming to the surface of the 

 ground after storms also serves as a means of repression, in that it 

 exposes them to the attacks of agencies of various sorts, including 

 man. Other atmospheric conditions are apparently inactive. 



A BACTERIAL DISEASE. 



A bacterial disease known as Micrococcus nigrofaciens has been 

 recorded from the larva of this species. 96 per cent of the larvae 

 obtained from North Carolina in 1913 showing slight infection. So 

 far as known, however, this disease exercises no appreciable effect 

 on the numbers of the host. 



MAMMAL ENEMIES. 



Many instances have been recorded of the destruction of white 

 grubs by wild mammals, such as foxes, raccoons, gophers, skunks, 

 and chipmunks. The last two mammals mentioned and the opossum 

 have been recorded as eating the grubs of this species. The much- 

 abused mole destroys large numbers of the grubs on lawns and some- 

 times in gardens, but unfortunately it is difficult to determine which 

 does the more damage to the lawns or gardens, the grubs or the moles. 



14 Specific identification by Dr. A. T. Speare, Bureau of Entomology. 



