B SECOND REPORT ON ECONOMIC BIOLOGY. 



those of cultivated crops remains to be seen. It frequently happens 

 that such is the case in the change of a food-habit of this kind, and 

 it is therefore doubly important that those individuals that migrated 

 from the Knotted Figwort to the Beet and Mangel should be 

 exterminated, and this I believe has been done in the present cases. 



DISTRIBUTION. 



Fowler 1 describes it as rather local, but common where it occurs. 

 He cites the following localities : " Darenth Wood, Coombe Wood, 

 Woking, Cowley, Aylsham and Potter Heigham, Norfolk ; Hastings ; 

 Winchester ; Southampton ; New Forest ; Glanvilles Wooton ; Devon ; 

 Bath ; Swansea ; Midland district, widely distributed ; Manchester 

 district, general ; Northumberland and Durham district ; Scotland, 

 Solway, Forth, Tay and probably other districts ; Ireland, near 

 Belfast, and most likely general." 



FOOD PLANTS. 



Hitherto the species of this genus have been regarded as feeding 

 only on plants belonging to the order Scrophulariacae, particularly on 

 species of Verbascum, such as V. thapsus, the Great Mullein, and 

 V. nigrum, the Black Mullein, and Scrophularia nodosa, Linn., the 

 Knotted Figwort, and S. aquatica, Linn., the Marsh Figwort, its 

 occurrence, therefore, on the Mangel and Beet is certainly strange, 

 but is only another instance of the change of feeding habits so common 

 amongst insects. 



LIFE-HISTORY AND HABITS. 



The eggs I have not seen, but they are probably laid on the under- 

 side of the leaves early in May. 



The larvae received by me on June i5th were variable in size and 

 seldom seen on the upper surface of the leaf. They usually commence 

 to feed at that portion of the leaf nearest to the petiole, eating away 

 the two layers of parenchyma ; later they returned and perforated the 

 leaf by feeding upon the upper layer of epidermal cells. Three typical 

 leaves of Scrophularia nodosa, Linn., are shown in Fig. 2. The 

 young larvae frequently fall off the leaves. Pupation commenced to 

 take place on the igth, the last examples pupated on the 22nd. 



'Coleoptera of the Brit. Islands, 1891, vol. v, p. 323. 



