6 



DEPARTMEISTT BULLETIN *ll9. 



yield of from 50 to 60 bushels, thrashed only 22 bushels of very 



inferior grain per acre. 



During 1915 when the grain bug was under close observation in 



northeastern New Mexico the visible damage before harvest varied 

 in many of the fields from only a trace to 50 per 

 cent of the heads, the average being about 10 per 

 cent. The full extent of the damage was not ap- 

 preciated until harvest, when the poor quality, 

 reduced yield, and light weight of the grain were 

 sources of general complaint among the farmers. 

 In one instance under consideration a carload of 

 oats averaged only 18 pounds per bushel. 



DESCRIPTION. 



Fig. 3. — T he grain 

 bug : Eggs. 'Above, 

 much enlarged ; be- 

 low, highly magni- 

 fied. 



THE EGG.i 



Length 1.1 to 1.2 mm. ; width at widest part 0.88 

 to 0.93 mm. ; width at bottom 0.57 to 0.66 mm. The egg 

 (fig. 3) is irregularly ovoid in form, with irregular gray 

 areas on the lateral surface, in appearance resembling 

 froth. Viewed from above, three white circles appear, 



inclosing a central dull-gray area and two circular bands of the same 



color. 



Described from 15 eggs taken from as many different clusters. 



NYMPHS.i 



KIEST INSTAK. 



Length 1.1 to 1.54 mm. ; width of thorax 0.88 to 0.935 mm. ; width of abdo- 

 men 0.935 to 1.072 mm. 



Dorsally: Head black, finely punctate, anterior margin sparsely pubescent ; 

 eyes black, prominent; antennae 0.77 to 1.88 mm. in 

 length, light brown, three terminal segments sparsely 

 pubescent. Thorax black, finely punctate, with deep 

 convolutions between its divisions and down the 

 median line. Abdomen brown-black in color, mid- 

 dorsal section occupied by a narrow black band ; 

 location of scent glands indicated by two black trans- 

 verse areas; a single black area within a yellow 

 border on the lateral margin of each segment and 

 a series of three irregular yellow-white markings 

 converging toward the apex of the abdomen. The 

 lateral margins of the abdomen and thorax are 

 greatly depressed and form a shelf-like division be- 

 tween the ventral and dorsal surfaces. This is distinct from the connexivum 

 of adult Heteroptera. The " shelf " persists throughout the nymphal period. 

 Edge of " shelf " sparsely pubescent in this instar. 



Fig. 4. — The grain bug : 

 Nymph, first instar. 

 Much enlarged. 



Original description. 



