624 Journal of Agricultural Research vol. vi, No. 16 



Winter form. — Head yellow to rich brown, varying to black at mouth parts and 

 to yellow on dorsal aspect; slightly bilobed. Prothoracic plate yellow. Body white. 

 Segmentation distinct. Crochets biordinal. Tubercles white or pale yellow, and 

 not easily distinguished from ground color of body, iv and v coalesced. Abdominal 

 tubercles ii oval and about twice as far apart as tubercles i. Primary setae yellow to 

 brown. Imaginary lines connecting setae i and ii, on each side, if prolonged, form 

 angles averaging 30. 2°. No secondary setae. Spiracles dark brown, elongate oval, 

 distinct and sharply contrasting with rest of body. Average length (10 specimens), 

 22.4 mm. 



Diatraea zeacolella Dyar. 



Summer form. — Head yellow, varying to black at mouth parts, slightly bilobed. 

 Prothoracic plate yellow. Body white. Segmentation distinct. Crochets biordinal. 

 Tubercles dark brown, contrasting sharply with ground color of body, iv and v coa- 

 lesced. Abdominal tubercles ii narrowed and about four times as far apart as tubercles 

 i. Primary setae yellow to brown. Imaginary lines connecting setae i and ii of abdom- 

 inal segments 3, 4, and 5, on each side, if prolonged, form angles averaging 53.3 . No 

 secondary setae. Spiracles black, elongate oval, distinct. Average length (3 speci- 

 mens), 25.2 mm. 



Winter Form. — Head yellow, varying to black at mouth parts, slightly bilobed. 

 Prothoracic plate yellow. Body white. Segmentation distinct. Crochets biordinal. 

 Tubercles white or pale yellow, and not easily distinguished from ground color of 

 body, iv and v coalesced. Abdominal tubercles ii narrowed and about four times as 

 far apart as tubercles i. Primary setae yellow to brown. Imaginary lines connecting 

 setae i and ii of abdominal segments 3, 4, and 5, on each side, if prolonged, form angles 

 averaging 53. 3 . No secondary setae. Spiracles black, elongate oval, very distinct 

 and sharply contrasting with rest of body. Average length (4 specimens), 24.5 mm. 



The writer has not seen all the instars of D. zeacolella Dyar. The instars 

 of D. saccharalis crambidoides are similar, except the first, which is de- 

 scribed below: 



Head black, more horizontal than in following stages. Prothoracic plate dark 

 brown. Body dirty white, widest at head and tapering caudally. Segmentation dis- 

 tinct. Prothoracic legs well developed. Elongate prolegs on protruding coxal lobes. 

 Tubercles prominent. Primary setae brown. No secondary setae. Average length 

 about 2 mm. 



Not only do the larvae of the two species vary in appearance, but their 

 food plants and breeding habits differ to some extent. The food plants 

 of D. saccharalis crambidoides include sugar cane, corn, and Johnson 

 grass and other large grasses. Practically all of the larval period is spent 

 within the stalks of the plants, except that the first instars feed about 

 on the leaves. D. zeacolella, however, seems to have a preference for 

 corn, even where sugar cane is present. Mr. U. C. Loftin found sugar 

 cane at Thomasville, Ga., absolutely uninfested, but Mr. G. D. Smith had 

 no trouble in obtaining larvae from cornstalks. The writer has examined 

 sugar cane at Waycross, Ga., without finding any larvae. One larva only 

 was found by Mr. Loftin at Chipley, Fla., in the sugar cane, and this is 

 the only one recorded from sugar cane. 



D. zeacolella goes far down in the taproots of corn, while D. saccharalis 

 crambidoides does not have this habit. This was observed bv Mr. E. R. 



