February, '13] NEWELL: RICE WATER WEEVIL 57 



hottest situations. Thus on June 4, at Crowley, I observed that a 

 much smaller proportion of the weevils were in direct sunlight than at 

 Lake Arthur. When it is hot, also, more of the weevils are found rest- 

 ing along the stems and a larger proportion rest and swim in the water 

 and under its surface. 



Feeding is not confined entirely to the leaves. A number of adults 

 were observed to make punctures in the main stem of the rice plant 

 below the water surface. I am satisfied that all weevils observed 

 feeding in this way were females, though the distinction between the 

 two sexes in the field is rather difficult and uncertain except when they 

 are observed in coitu. The injury made by the feeding below the 

 water line is quite distinct from that done to the leaves above water. 

 In the former case distinct punctures are made with the beak, not 

 unlike the punctures made in cotton squares by the boll weevil. 



Host Plants. Cultivated rice is the preferred host and food plant, 

 and but little difference is noted in choice between Honduras and 

 Japanese tjqDes. In general, it may be said that the adults prefer to 

 feed on young plants, rather than on those of advanced size. Infes- 

 tation of the rice field by the adults is invariably co-incident with the 

 first flooding. 



Doctor Howard, in the article referred to, recorded several plants 

 which were fed upon by the adults, particularly wild rice, bulrush, 

 w^ater lily and spatter-dock. 



In the course of my Louisiana observations, I found but two food 

 plants and but one true host plant, other than cultivated rice. Wild 

 rice, Zizania aquatica, did not, however, come under my observation, 

 and it is to be expected that this is a true host plant. 



On June 3, at Lake Arthur, I found the adult weevils feeding as 

 freely upon the leaves of Paspalum membranaceum Walt, as upon the 

 rice leaves, with which they were interspersed. The same habit was 

 subsequently observed in all infested fields. Upon another Paspalum 

 the adults fed as freely as upon P. membranaceum and on June 29 

 this Paspalum, growang in isolation from rice, was found to have its 

 roots heavily infested with the water-weevil larvse. This Paspalum 

 was never positively identified and while apparently different in habit 

 of growth from membranaceum, it may possibly be a variety of that 

 species. It is about the first grass to begin growth in spring, occupy- 

 ing drainage ditches, shallow ponds and all places where shallow 

 water is available. It was noticed growing abundantly in the street 

 ditches of Crowley, La., in the spring of 1909. At that time I did not 

 suspicion it of being a host plant of the water-weevil and its roots 

 were not examined for the larvse. 



Attraction to Lights. The adults fly readily to artificial light of all 



