152 MUSTARD. 



These beetles pass the winter in a torpid state, in any con- 

 venient shelter near the fields where they have been in the 

 autumn. In the sjDring they become active again, and spreading 

 to whatever food-plant may be near, they lay their small eggs 

 and die. 



The grubs, or larv?e, which hatch from these eggs,* are of 

 the shape shown in fig. 1 (p. 151), and are from about three- 

 sixteenths to a quarter of an inch in length when full-grown, 

 slightly hairy, of a smoky colour, spotted with black, with 

 black heads and stout black conical horns, lighter at the base. 

 They have three pairs of claw-feet, and a caudal foot, or pro- 

 leg, at the end of the tail, and a row of tubercles along each 

 side, from which the grubs have the power of protruding a 

 yellow gland. These voracious grubs devour far and wide, until 

 when full fed they go into the ground to change to chrysalids. 

 In this state they are said to remain about fourteen days, and 

 from these chrysalids the summer brood of beetles comes out 

 which often spreads devastation over the Mustard crop, then in 

 an advanced state. 



The first observation (as far as I am aware) of remarkable 

 appearance of this pest was in 1854, when Prof. Westwood, in 

 reply to enquiry regarding beetles sent him for examination, 

 stated : — " The little beetles which are attacking the White 

 Mustard crops in the Fens, near Ely, are the Clirysomela 

 (Phadon) hetulcE. Such a fact has not j^reviously been recorded.''^ 

 After this date the attack of the Mustard Beetle, commonly 

 known as "Black Jack," was reported at intervals, until in 

 1885 it was noticed as having become such a frequent and 

 serious evil as to need investigation, and in 1886 circulars 

 were issued by the Eoyal Agricultural Society of England, re- 

 questing observations from Mustard-growers regarding the 

 habits of the beetle, and measures found serviceable for pre- 

 venting its ravages. An abstract of the information received 

 was formed by myself (as Entomologist of the Society) into a 

 report printed in vol. xxiii., pt. 1, of the second series of the 

 Society's Journal, and the contributors' information was given 

 in detail in my own Report on Injurious Insects for 1886. 

 From the above notes a portion of the following observations 

 are taken. 



Where siyring attach comes from. — The observations showed 

 that this was from almost any kind of available winter shelter. 

 The beetles were stated to lie dormant during the winter in 

 pipes or reeds ; in the ends of old Mustard-stocks left on the 



* I have identified the grub from specimens kindly procured for me by 

 Mr. George Moore, of Wisbech, from Mustard-plants near Ely, which enabled 

 me to trace the insect from larval condition up to its perfect state, and confirm 

 the figure and description given (doubtfully) by John Curtis in his ' Farm 

 Insects ' as being certainhj (hat of Ihe larva of the Phwdoji betnhc. — (E. A. 0.) 



