412 



Observations on the various Insects 



lettuce whilst growing upon the plants ; others revel in the decay- 

 ing stems of cabbages, the bulbs of turnips and of onions ; whilst 

 others reside between the two skins of the leaves, feeding upon 

 the pulp — and these have received amongst naturalists the name 

 of miners. A gentleman at Cranford, who is well known for his 

 scientific researches,* has made me acquainted Avith a fly whose 

 larva mines in the leaves of the mangold- wurzel, and I am in- 

 debted to him for the following sketch of its economy : — " The 

 maggots were brought to me from Surrey on the 26th of June, 

 found feeding between the plates of the leaves, the integuments of 

 which they cut rapidly, giving the parts attacked a blistered ap- 

 pearance. They were of a greenish colour, a quarter of an inch 

 long, pointed at the head, and rather abruptly cut off at the tail : 

 they turned to pupae in situ, as you may see by the frag- 

 ments of the leaves, and hatched July the 17th and 20th: Mr. 

 Frogley told me they had destroyed the plant where he got them 

 from. I found my sugar-beet attacked in the same manner, but 

 immediately employed some boys to pinch the blisters between 

 the finger and thumb, and by attacking them in that helpless 

 situation their operations were effectually stopped." 



I may remark, that the maggots are very similar to those of 

 the turnip ;t like them, they change to an oval brown pupa, and 

 from them issues a fly which exceedingly resembles Anthomyia 

 Cejiarum, which is bred from putrescent onions, but, as 1 cannot 

 imagine they are the same species, I must distinguish them by 

 naming the former, and shall call it after the beet or mangold- 

 wurzel : — 



5. A. Betse. The ^nales only are known at present : they are much 

 smaller than the Onion-fly, being only 2 and f lines long, and expanding 

 about 5 lines : they are of an ashy-grey colour, clothed with black 

 bristly hairs ; head semi-orbicular ; eyes large, brown, nearly contigu- 

 ous above, with 3 minute ocelli on the crown ; face satiny-white, with 

 a bright chesnut-coloured line down the middle, in the centre of which 

 are placed the little black drooping horns, the 3rd joint being the 

 largest, elliptical, and producing a naked bristle on the back; the pro- 

 truded lip and palpi are also black: on the trunk are 3 or 5 indistinct 

 longitudinal stripes; the 6-jointed abdomen is linear, with a dorsal black 

 triangular spot at the base of 4 of the segments ; the 2 wings are ample 

 and transparent, a little tinted with tawny at the base; the nervures are 

 pitchy ; poisers ochreous ; 6 legs, longish, bristly, and pitchy, the shanks 

 with a tawny tinge. 



These insects will seldom cause any loss to the mangold-wurzel 

 crops, should they ever abound to any extent; but whether 

 they would prove injurious to cattle when the leaves are given as 



- Mr. F. J. Graham, author of a Prize Essay upon the Potato Disease 

 t Royal Agric, Jour., vol. iv. pi. R figs. 35 aiid 36. 



