SCOLYTID^. 



491 



The Potato-stalk Weevil, Baridius trinotatus Say (Fig. 471 ; 

 a, larva; &, pupa; c, adult), is a common species in the Mid- 

 dle and Western States, where it causes the stalk to wilt and 

 die, hence all stalks so affected should be burnt. "The beetle 

 is of a bluish or ash gray color, distin- 

 guished as its name implies, by having 

 three shiny black impressed spots at the 

 lower edge of the thorax. The female 

 deposits a single egg in an oblong slit ^^s- 4*0. 



about one -eighth of an inch long, which she has previously 

 formed with her beak in the stalk of the potato. The larva 

 subsequently hatches out and bores into the heart of the stalk, 

 always proceeding downward towards the root. When fully 

 grown it is a little over one-fourth of an inch long, and is a 

 soft, whitish, legless grub, Avith a scaly head." (Rile^^) Fig. 

 472 represents the larva of 

 JB. vestitus Schonherr, which 

 bores into the stems of the 

 tobacco plant in Mexico. 



Mr. Huntington has ob- 

 served the Grape Cane gall 

 curculio, Baridius Sesostris 

 Lee. (Fig. 473) in the larval 

 state in large bunches near the joints of the Clinton grape on 

 Kelly's Island, near Sandusky, Ohio, and has also found the 

 beetle in considerable numbers. The larva closely resembles 

 that of the Potato Baridius. Riley states that the gall 

 is formed during the previous autumn while the tender 

 cane is growing. "It has almost invariably a longitu- 

 dinal slit or depression on one side, dividing that side 

 into two cheeks, which generally have a rosy tint." 

 It pupates late in June, and early in Jul}^ the adult Fig. 472. 

 appears. It ma}^ be' known by its polished elj'tra and punc- 

 tured thorax. It is pale reddish, with a stout beak, equalling 

 the body in length, and each elytron has a swelling on the 

 outer edge near the base, and another near the tip. It is a 

 tenth of an inch long. It is the Madams vitis of Riley. 



Fig. 471. 



ScoLYTiD^ Westwood. These cylindi-ical bark borers are 



