THE EOUGH-HEADED COEN STALK-BEETLE 23 



of the egg-laying generation of the year have perished by the first 

 of August. 



At Tappahannock, eggs, or recently hatched larvae, were found in 

 hills of corn and in a layer of vegetable mold. In this vegetable 

 mold they were often deposited at the base of tussocks of the common 

 rush, beneath clumps of pasture grasses, especially those of the genus 

 Paspalum, and under low mats of Japan clover. The eggs hatch 

 within two or three weeks under normal summer conditions. 



ACTIVITY IN THE SPUING 



The beetles are unquestionably much more active and attract far 

 more attention in the spring than during the fall. This is due doubt- 

 less to the activities connected with feeding and reproduction. The 

 beetles are rather sluggish, and if their needs are adequately met they 

 apparently do not roam much. When, from any cause, their needs 

 are not satisfied, they may come out of the ground and go elsewhere 

 in search of more favorable locations, either by flight or by crawling 

 away on the surface. Apparently the beetles fly only at night, when 

 they are frequently attracted to lights, but the junior writer has 

 repeatedly observed them crawling on the surface in bright daylight. 



From observations made on caged individuals, it would appear 

 that the impulse to wander may come from lack of food as well as 

 from the instinct to mate. Thus, in cages in which beetles were con- 

 fined without food, they often came out on the surface, especially at 

 night, and crawled up the sides of the cages, frequently • attempting 

 to take flight; whereas in adjoining cages, in which the inmates were 

 plentifully supplied with food, it was a rare event for one to be 

 found on the surface at any time. A beetle has occasionally been 

 observed to emerge from a hill of corn in which all the plants had 

 been killed and move off to another where the plants were intact. 



FOOD PLANTS AND CHARACTER OF INJURY BY THE BEETLE 



Euetheola rugiceps is best known as an enemy of corn and sugar 

 cane, but there is reason to believe that these are not its normal food 

 plants. During the fall of 1915 the junior writer found them feed- 

 ing abundantly upon certain species of grasses belonging to the genus 

 Paspalum. These grasses have since been found in every section 

 visited by him in which the species has been found or from which it 

 has been reported, and there is accordingly every reason to believe 

 that they constitute the favorite food of the beetles. Beetles kept in 

 confinement ate the plants eagerly. At Tappahannock the species of 

 Paspalum fed upon were determined as P. laeve- and P. plenipilum. 

 The large, coarse-stemmed forms, such as P. fioridanum, do not ap- 

 pear to be acceptable to them. The beetles attack these grasses in 

 much the same manner as they do corn, forcing their way beneath 

 the tufts, or coming up under them from below, and boring into the 

 culms where the latter lie in contact with the ground. Sometimes 

 the culms are cut completely off, but even when they are not entirely 

 severed such a thin and broken bit of tissue is left connecting the 

 parts that the portion beyond the injury quickly wilts and dies. In 

 the full of 1015 it was a common occurrence to find large patches of 

 Paspalum which had been almost or quite completely destroyed by 

 them. 



