THE GEAIN BUG. 31 



beneath the surface of the ground, as many individuals in this stage 

 have been dug from the soil underneath the hibernating quarters early 

 in the spring. This fact was not definitely established, however, ow- 

 ing to the difficulty encountered throughout the winter in examining 

 the frozen soil of these locations. 



Eight specimens of the tachinid Ocypterodes euchenor Walk, were 

 reared from several hundred adults of CMorochroa sayi kept in con- 

 finement during 1916. The species has been observed infrequently 

 in the field and must be considered of only minor importance in the 

 natural control of C. sayi. Its life cycle and habits, as far as ob- 

 served, were very similar to those of Gyinnosoma fuliginosa. 



PREDACIOUS ENEMIES. 



The offensive odor secreted by the scent glands of Chloroohroa 

 sayi has been commonly supposed to protect them from the attacks 

 of predatory enemies. Wliile this odor may act as a repellent to 

 some of its enemies, in the case of C. sayi the different stages of the 

 insect are preyed upon by quite a variety of both vertebrate and in- 

 vertebrate enemies. Considered individually these enemies are not 

 of great importance in the control of the pest, but in the aggregate 

 they undoubtedly exert considerable influence in the reduction of its 

 numbers. 



PREDATOEY INSECTS. 



The adults of the malachiid beetle Collops hipunctatus Say 

 feed upon the eggs of CMorochroa sayi in the field. This small 

 beetle is very numerous in the grain fields of New Mexico and ap- 

 parently is one of the most effective predatory enemies of the grain 

 bug. In confinement a single adult of this species devoured in one 

 day an egg cluster consisting of 10 eggs, consuming even the egg- 

 shells. The same individual, however, refused to feed upon small 

 nymphs of C. sayi. 



When confined in cages the adults of C. sayi frequently fed upon 

 their own eggs, but this habit has not been observed in the field. 



The adults of Sinea spinipes H. S. and of Phymata erosa Stal 

 have been observed feeding upon the nymphs of the grain bug in the 

 field. 



BIEDS. 



The Bureau of Biological Survey reports that CMorochroa sayi 

 has been found in the stomachs of the nighthawk {Chordeiles vir- 

 ginianus) and the meadowlark {Sturnella neglecta)^ and that indi- 

 viduals of other species of the same genus have been found in the 

 stomachs of the bob white [Colinus virginianus) , kingbird {Tyran- 

 nus tyrannus)^ Brewer blackbird {Euphagus cyanocephalus) , Frank- 

 lin gull {Larus franklini)., and English sparrow {Passer domesticus) , 



