8 BULLETIN 539, U. S. DEPARTMENT OF AGRICULTURE. 



The soil in these plats was of a sandy nature. He further stated that 

 a report was received from Boca Grande, Fla. ; that 2 of 18 acres of 

 cowpeas had been destroyed by this pest. Mr. R. N. Wilson, of the 

 Bureau of Entomology, who was instructed to investigate this 

 infestation more fully, confirmed Mr. Dozier's statement, young 

 plants being injured by the larvae boring into and upward in the 

 stems, while in older plants the stems were girdled at or slightly 

 below the ground. The result in v both cases was that the injured 

 plants wilted and died, although it was noted that in exceptional 

 cases the plants, being vigorous, overcame the injury. Mr. Wilson 

 further submitted a letter which had been received from Mr. Joseph 

 Crews, farm demonstrator at Arcadia, Fla., stating that the ■" worms" 

 injured cowpeas, Japanese cane, corn, and chufa. Cowpeas wero 

 damaged to some extent in the stiff black soil, but more serious 

 damage was done in the sandy soil. This soil had all been well limed 

 and heavily fertilized. Damage was done to Japanese cane planted 

 in an old piece of land which was cleared years ago bnt had not been 

 under cultivation for a number of years until the present. At least 

 90 per cent of the crop was damaged and the crop lost about 50 per 

 cent in value. 



While the increasing number of records of damage by this insect 

 in the last few years is due in part to the fact that injury by it is more 

 likely to be reported now than was the case years ago, it is also prob- 

 able that the species is slowly modifying its habits to correspond 

 with modern methods of agriculture and that, in the future, occasional 

 outbreaks, perhaps more severe than any yet recorded, may be 

 expected unless means are taken to check them in advance. 



DESCRIPTIONS. 1 



THE EGG. 



The egg (fig. 2) is ovate, circular in cross section, 0.67 mm. in length and 0.46 mm. 

 in diameter; greenish white when first deposited, pinkish in from 18 to 24 hours, 

 an approximate Alizar crimson with a tinge of yellow at end of 

 incubation period; strongly iridescent. Exochorion sculptured 

 with shallow pits pentagonal to polygonal in outline. Endocho- 

 rion apparently smooth. 



LARVAL INSTARS. 



First instar. — Length 1.7 mm. Head slightly bilobed, flattened, 

 ***&&§$? highly polished dark brown, width 0:23 mm., about as high as wide; 



Fig. 2.— The lesser clypeus triangular, 0. II mm. high. Paraclypeal pieces not percep- 

 corn stalk -borer: tible, region dusky; labrum pale, tips of mandibles reddish brown, 

 lanred (OriginaJn not projecting; setae 0.11 mm. long; antennae pale, moderate. Cer- 

 vical shield almost straight in front, much rounded behind, one 

 not quite as wide as the head. Prespiracular tubercle bears 2 setae, the upper of the 

 two being the shorter; subventrical tubercle also bears 2 setae, the cephalad one being 



1 Descriptions by senior author. Measurements of all stages made from alcoholic material. That given 

 for the length of larva in stage "> is a little low on account of insufficient material on hand for a better 

 average. 



