332 SUBFAMILY X. CURCULIOXIXJE. 



thorax oblong, conical, its base Insinuate; scutellum minute, tri- 

 angular; elytra elongate, subeylindrical, as wide at base as 

 thorax, their sides usually continuous, humeri obtusely suban- 

 gulate; tarsi broad, spongy beneath, with the third joint deeply 

 bilobed. 



Schonherr, who founded the genus Clconus, states (1836, 2) 

 that Li, FII ft differs from it chiefly in haying the "antennis pone 

 medium, hand apici rostri insertis, teuuioribus ; rostro tereti, 

 Irevi, nee distincte carinato neque canaliculate; corpore etiam 

 srepissime minus crasso," but as will be seen, these distinctions 

 do not apply to a number of our species accredited to Li.nts. For 

 example, the point of insertion of the an ten lire is a sexual rather 

 than a generic character, as they are almost always inserted 

 nearer the apex in the male than in the female. Again, certain 

 of our species ha ye the beak distinctly carinate, while others haye 

 the body as stout as in any species of Clconus. 



Most of the species, when fresh, are coyered with a pollen-like 

 yellowish powder which is easily rubbed off, and many of them 

 are pubescent. They are stem weeyils, the lary;e frequently caus- 

 ing an elongate, gall-like swelling of the stems of various plants. 

 Pupation takes place in the burrow or gall, and there is generally 

 only one generation a year. The texture of the elytra is remark- 

 ably hard, it being very difficult to impale them with ordinary 

 insect pins. About 40 species of Li.rus are known from the 

 United States, 21 of which occur in our territory. For conven- 

 ience they are separated into two groups: 



KEY TO GROUPS OF EASTERN SPECIES OF LIXUS. 



a. Second joint of funicle either shorter or subequal in length to the 



next two combined. GROUP I, p. 332. 



act. Second joint of funicle slender, distinctly longer than the next two 



combined; elytra usually more or less finely mottled with ash-gray 



pubescence. GROUP II, p. 340. 



GROUP I. 



KEY TO SPECIES OF GROUP I. 



a. Tips of elytra prolonged in short, rather acute, feebly diverging pro- 

 cesses. 



1). Form stout; color black; first joint of funicle very short, not as 



long as third and fourth combined. 497. CAUDIFER. 



1)1). Form slender; color reddish-brown; first joint of funicle equal to 



third and fourth combined. 498. UUBELLUS. 



an. Tips of elytra not prolonged. 



c. Elytra and thorax with a narrow, abruptly limited, densely pubes- 

 cent marginal pale stripe. 



