286 PROCEEDINGS OF THE 



M. DuPONCHEL read a letter which had been addressed to 

 him by M. Daube, a member of the Society, on the subject of 

 Colaspis barbara, Fab. *' It were much to be desired," said 

 the writer, " that the insects in question, denounced previously 

 in the ' Annales^ as injurious to farmers, were confined to the 

 kingdom of Valence ; every year our lucern, after the first 

 cutting (that is to say in the month of June), is devoured by the 

 larvae of this insect. If, instead of collecting the larvae in a net, 

 as is the present practice, they were to collect and destroy the 

 perfect female, there is no doubt but a better result would 

 follow. Indeed, from a plant so bushy as the lucern, one can 

 only sweep into the net those larvae which happen to be on the 

 tops: and as the larvae fall at the least movement of the plant, 

 it is very difl[icult to destroy any considerable number, even 

 though the operation be continued repeatedly. I employ the 

 following plan, which I consider every way preferable ; for if 

 it does not entirely destroy the evil, it undoubtedly greatly 

 abates it. The Colaspis barbara begins to appear in the 

 beginning of May. At this period they may be found m copula, 

 and closely adhering to the stem of the lucern. Some days 

 after, the males disappear, and the females, with bodies remark- 

 ably increased in size, being no longer able to use their wings, 

 run hither and thither to deposit their eggs. The laying of 

 eggs continues from eight o'clock in the morning till between 

 two and three in the afternoon. Nothing is more easy than to 

 take the females during the operation ; for they lay the eggs at 

 the very tips of the lucern, and the enlargement of their 

 bodies renders them very conspicuous. Every female lays, in 

 my opinion, about 500 eggs ; now, if a woman were employed 

 in collecting them, supposing she gathered but 2000 per day, 

 it is evident how many would be destroyed, for the period of 

 oviposition lasts but from ten to twelve days. I had this year 

 a field of lucern enclosed by walls ; and perceiving that the 

 lucern in the neighbourhood was already becoming a prey to 

 this insect, I employed a woman, who, in eight days, collected 

 from thirty-five to forty kilogrammes of the females. By this 

 means I have had the pleasure of cutting a hundred quintals of 

 lucern at a time, when the crops of my neighbours have been 

 entirely destroyed. Having no longer any thing to eat, the 

 larvae attacked the santfoin, and even the wheat. M. Daube, 

 in the same communication, mentions the injury done to the 



