MUSTARD BEETLE. 91 



Many kinds of dressings, or washes, have been brought forward, some 

 of which we know are beneficial in getting rid of similar attack in 

 similar circumstances, and also much greater variety of implements 

 for distribution of the sprays, or washes, are now available. 



Under these circumstances much increased attention has been 

 given to possibility of checking attack, whether of the grubs or beetles 

 when present, and it is proposed in various localities to experiment, 

 both as to effects of applications which there is reason to suppose may 

 be of use, and also with regard to possibility of giving access amongst 

 the crop to the requisite implements, or to bearers of implements for 

 their distribution. 



Much inquiry has been sent to myself as to what could be done for 

 destruction of the infestation, and (as desired) I have endeavoured in 

 the following pages to give the main points up to date of what is known 

 as to the history of the insects, and available methods of prevention (to 

 some degree), if not of remedy of its ravages. Also the measures 

 which, from result of parallel experiment, that is, on the same nature 

 of insects and of crops, appear likely to be of service. 



There are several kinds of beetles which infest the Mustard crop, 

 but the one especially known as " The Mustard Beetle," is of a deep 

 full blue or greenish colour above (so shiny as to be almost of a glassy 

 lustre), and black beneath. The legs and horns are also black. It is 

 oblong oval in shape, about the sixth of an inch long, slightly punctured 

 on the back, and has two wings. 



The grubs, which are of the shape figured at p. 90, are about a 

 quarter of an inch in length when full-grown, slightly hairy, of a 

 smoky colour, spotted with black, with black head, and stout black 

 conical horns, lighter at the base. They have three pairs of claw-feet, 

 and a sucker-foot at the end of the tail, and along the sides of the body 

 are a row of tubercles, from which the grubs have the power of pro- 

 truding a yellow gland.* 



The method of life is for the beetles to winter in any convenient 

 shelter, in the most various kinds of localities. It may be in the ends 

 of Mustard stocks, or in the roots of old Mustard plants left on the 

 land, or in rough shelters made of Mustard straw. In ditch or hedge- 

 banks, in the earth or in the rough grass, or at the bottom of hedge- 

 rows. Also they are to be found in crannies of walls, gateposts, old 



* A good description of these grubs will be found in Curtis' ' Farm Insects,' p. 

 72, with the observation that he considered it far from improbable that they were 

 the larvae of the Phcedon hetiila, but (as the point did not appear to have been 

 further gone into) in the course of my own observations I reared some of the grubs 

 up to beetle state, and found that these larvae (precisely corresiionding with Curtis' 

 description) turned, as he surmised, in due season to the PhcBdoii betidce, or 

 Mustard Beetle. 



