622 



Journal of Agricultural Research 



Vol. VI. No. 16 



that D. saccharalis occurs throughout the Southern States. Referring 

 to Dyar's paper, he noticed that the range of D. saccharalis crambidoides 

 is given as "Mexico, numerous localities, Gulf States, and lower Mis- 

 sissippi Valley," a range which roughly covers the limits which in num- 

 erous field trips have since been defined more exactly. Dyar records D. 

 zeacolella only from points in North Carolina, South Carolina, and 

 Virginia. 



To compare larvae from these sections with the more southern species, 

 the writer obtained specimens from various members of the staff of the 

 Bureau of Entomology from the following places: Columbia and Ben- 

 nettsville, S. C, and Waynesboro, Ga. (E. R. Barber); Batesburg, S. C. 

 (E. A. McGregor); Thomasville, Ga. (G. D. Smith). All these larvae 

 were from corn. A casual examination was sufficient to show that 

 they differed from D. saccharalis crambidoides. The most apparent dif- 

 ference is that the larvae (summer form) from the places mentioned 

 above have a clean-cut black-and-white appearance, while larvae of D. 



Fig. i. — a, Average angle formed by imaginary lines through bases of setae of Diatraea saccharalis crambi- 

 doides; b, average angle formed by imaginary lines through bases of setae of D. zeacolella. Dots indicate 

 bases of setae. 



saccharalis crambidoides (summer form), because of the lighter color of 

 the tubercles, are of a more neutral color, which may be described as a 

 kind of dirty white. That the strikingly marked larvae were D. zeacolella 

 was proved by an inflated specimen of the same species in the National 

 Museum, which had been classified by Dr. Dyar as D. zeacolella. It was 

 labeled, "On corn, Peacocks Store, N. C." 



When the larvae were shown to Mr. W. Dwight Pierce, of the Bureau 

 of Entomology, he immediately observed a difference in the pattern of 

 the dorsal tubercles (i and ii), the four tubercles of a segment of D. zea- 

 colella roughly forming a trapezoid and those of D. saccharalis crambi- 

 doides forming a more rectangular figure. At the suggestion of Dr. W. 

 D. Hunter, in Charge of Southern Field Crop Insect Investigations, and 

 with the aid of Mr. August Busck, of the Bureau of Entomology, and 

 Rev. J. J. De Gryse, at that time stationed at the Eastern Laboratory of 

 Forest Insect Investigations, the writer proceeded to study the larvae of 

 the two species for further differences. While the pattern of the dorsal 

 tubercles is valuable, their color fades in the winter, and it is then rather 



