April 1, 1930 Banana Root Borer 41 



tap root, but is supported by numerous lateral roots (PL 11, A). An indi- 

 cation that a young plant is infested is the withering and drying of the 

 curled roll of unopened leaves or growing part of the plant. The root, 

 upon examination, is found to be riddled with the larvae of this insect 

 and when cut open discloses the borer in situ. The adult weevils are 

 abundant in the soil about the root and also are found under loose fiber 

 surrounding the base of the stem, at the crown. They also congregate in 

 the cavities caused by the larvae at the base of the bulb of the banana 

 plant. In the planting at Larkins, Fla., where the infestation was first 

 found, the writer collected 55 adults at the base of one plant and as 

 many as 60 larvae and pupae in the bulb. The older plants infested ap- 

 peared tall and spindling and no doubt succeeded in growing as much as 

 they did by the presence of numerous lateral roots surrounding the 

 bulbs of the plants and because the attacks of the insects had been 

 gradual. Most of the bananas in the planting were old and so riddled 

 by the lan.^ae as to be readily felled. After feeding thoroughly on a 

 plant the weevils abandon it for another. 



TECHNICAL DESCRIPTIONS OF THE SPECIES 



The following descriptions by Dr. W. Dwight Pierce are based upon 

 specimens collected at Larkins, Fla., January 19, 1918. The fine draw- 

 ings accompanying the descriptions were made under Dr. Pierce's super- 

 vision by Ml. Harry Bradford and by Dr. Adam Boving. 



EGG 



The egg is elongate oval, about 2 mm. in length, rounded at one end and more or 

 less pointed at the other, and pure white in color. 



LARVA (Ply. 9, B-G) 



The larva is characteristically calandrid in form (PI. 9, B), having the eighth and 

 ninth segments transformed into a sort of pygidial plate bearing very large elongated 

 spiracles on the eighth segment (PI. 9, F, G). The other abdominal spiracles are all 

 very minute and indistinct. The mesothoracic spiracles are very large. The length 

 of a full-grown larva is at least 13 mm. (The writer has not had a live specimen to 

 measure.) The body is white and the head shield dark reddish brown. The head 

 is quite prominent. The head shield is broadly, elongately emarginate behind (PI. 

 9, C). From the center of the emargination on the median line the epicranial suture 

 passes forward, separating the epicranium into two parts (PI. 9, C). This sutiue is 

 strongly marked with black on its posterior half and is white from thence forward to 

 the frons, behind which it divides and forms two frontal sutiu-es (PI. 9, D). 



The frons (PI. 9, D) is subtriangular, emarginate at anterior angles for the antennje, 

 and emarginate along the epistoma for attachment of the clypeus. The median line 

 is faintly indicated by a dark line in the basal half. The frons has two pairs of large 

 setae and two pairs of tiny setae ; the three posterior pairs, the last of which is the small- 

 est though the first is also small, form a triangle, the first and last pairs being almost 

 equidistant. The anterior or epistomal pair of setae are large and are attached 

 opposite the basal angles of the clypeus and some little distance from the antennal 

 fosscE. 



