64 MUSTABD. 



in destructive power next after the true Mustard Beetles, and to be 

 very often not distinguished from it.* 



With regard to these, the Plmclon hetulce, as I am not aware of 

 the method of deposit of the eggs, and hatching out of the larvae, being 

 generally known, I add the following details from my own observations. 



On the 2nd of June, a very good supply of Mustard leaves, on 

 which eggs of the Mustard Beetle, Plmdon hetuLm, had been deposited, 

 were sent me by request of Messrs. J. and J. Colman, of Carrow Works, 

 Norwich, from Littleport Bridge, near Ely, per favour of Mr. Smith 

 Flanders, for examination as to possible effects on the eggs of a 

 dressing which had been applied five days before. The leaves were 

 sent me tied up in two bunches, one bunch consisting of the leaves 

 which had been dressed, the other bunch (duly distinguished and sent 

 for comparison of condition of the eggs) of leaves to which no dressing 

 had been applied. 



These leaves I placed with the tips of their stalks in water, in a 

 room of ordinary temperature, but two days later (on June 5th), as the 

 eggs were unaltered in appearance, I moved the leaves to a room with 

 a south aspect, where a window was open close to them during most 

 of the day. 



The eggs were smooth, cylindrical, and blunt at the ends, and 

 yellow in colour ; and for the most part were placed longitudinally by 

 the side of the mid-vein, or one of the side veins, on the back of the 

 leaf. They were very rarely indeed not placed by a vein, and (as far 

 as I saw) never on the upper side of the leaves. They were placed in 

 a little hollowed-out space, so that the egg rested in the substance of 

 the leaf, against the inside of the upper skin of the leaf, and they were 

 usually (although not invariably) covered by what appeared to be dead 

 and discoloured remains of the skin of the little patch of hollowed-out 

 leafage in which they rested, but, any way, by some adherent and 

 protective rubbish. 



The eggs appeared to be in healthy condition, that is, bright, shiny, 

 and plump (not shrivelled or discoloured) when I examined them 

 shortly after receipt, but I could not find as yet any formation of the 

 larva, or grub, then taking place within, excepting perhaps in a few 

 instances, and on pricking them a yellow fluid ran out ; it was not 

 until the 7th of June that they began to hatch, and on the following 

 day I was able to watch the emergence of the larva, and its changes of 

 colour, in detail. 



The shape and colour of the egg could now often be seen through 



* The above note on the " Turnip-flower Beetle," as well as that on the " Mus- 

 tard Beetle," I have given nearly verbatim from my leaflet above mentioned, of 

 which I should be happy to offer copies to any applicant. — (E. A. 0.) 



