69 



INJUBIES TO VEGETATION. 



As larvse these species live aud feed, as far as known, in the 

 roots of grass-like plants, less commonly boring also the lower 

 part of the stem. Grasses with bulbous roots, like timothy and the 

 club rush, are probably their more normal breeding plants. In 

 timothy meadows the hollowing out of the root bulb frequently 

 kills the plant, — if not outright, then the following year. The 

 larger club rush seems to endure better the attack of the clay- 

 colored bill bug, as several successive bulbs of a series are often 

 found excavated, each having given origin to its plant notwith- 

 standing the injury. 



The natural food of the robitstus larva is unknown, as this has 

 been found feeding only in corn. "Wherever," says Mr. Howard, 

 "the larva has reached its full size, the pith of the stalk was 

 found completely eaten out for at least five inches. Below ground 

 even the hard, external portions of the stalk were eaten through, 

 and in one instance everything except the rootlets had disappeared, 

 and the stalk had fallen to the ground." 



"In a great majority of instances but a single larva was found 

 in a stalk, but a few cases were found where two larvse were 

 at work. In no case had an ear filled on a stalk bored by this 

 larva. The stalk was often stunted and twisted, and the lower 

 leaves were invariably brown and withered." 



The larva of parviilus eats into the grass bulb, commonly from 

 beneath, completely hollowing it out, and scattering a fine meal- 

 like excrement through the earth. The harm thus done is sometimes 

 considerable,- -five i^er cent, or more of the stems being deadened, 

 — but has never been severe, as far as I now know. In small 

 grain, according to Mr. Webster, parvulus hollows out the stem 

 between the first and second joints above the ground, aud in 

 corn, burrows in the lower part of the stalk. A small Sphenophorus 

 larva found occasionally in the lower part of wheat stems in June, 

 1887, by my assistant Mr. Weed, belongs to this species. 



The natural food of the adult ochreus is, at first, the club rush, 

 in whose roots the larva breeds, as was shown in the swamps of 

 Ford county by the very general and profuse perforation of the 

 leaves of this rush where the beetles were themselves abundant. 

 By the end of June, however, this plant had become too hard for 

 them, and then the beetles were seen feeding in numbers on the 

 terminal leaves and forming spray of blossoms of the common 

 reed {Fhrarjmites communis), which were rolled together in an 

 oblong mass at the tip of the stalk. This they were piercing 

 and splitting lengthwise, afterward eating out the succulent young 

 vegetation from within. 



The adults of all the species feed in substantially the same 

 manner, as far as observed, and inflict a similar injury on the 

 plants they infest. Standing with the head downward and the feet 

 embracing the lower part of the stalk, they slowly sink the beak 

 into the plant, using the jaws to make the necessary perforation. 



