242 OBSERVATIONS ON INSECTS. 



pearance blistered, not knowing the cause from which 

 it proceeded. Every one of these knobs, however, 

 contains a maggot, which is at once obvious on cut- 

 ting into them. Being desirous of ascertaining the 

 species they belonged to, I put several of the dis- 

 eased roots into a large glass jar, having some earth 

 at bottom, and covered with gauze at top to prevent 

 the escape of the perfect insects, whenever they 

 should appear. I waited three or four months in 

 expectation of their coming out, but none shewed 

 themselves. At the end of this time the turnips 

 were rotten and stinking; but, on examination, 

 the maggots were still in them and alive. At last, 

 quite at the end of the following June, when the 

 turnips were almost liquid from putrefaction, the 

 insects appeared in large quantities. They proved 

 to be the Ceutorhynchus sulcicollis.* 



LIXUS PRODUCTUS.f 



THIS singular-looking and rather local insect is 

 very common in some parts of the fens of Cambridge- 

 shire, inhabiting the stems of the great water-parsnep 

 (Sium latifolium), on the pith and internal membranes 

 of which the larvae feed. During the first week in 

 August 1827, I noticed several of these last in plants 



* They were so named by Mr. Stephens, to whom I shewed 

 them. Kirby and Spence, who have noticed this disease of the 

 turnip, (vol. i. 1st edit. p. 186,) attribute it to the Rynchtenus 

 assimilis, F. (Nedyus assimilis, Steph.) ; perhaps there may be 

 more than one species of insect that causes it. 



f Steph. Man. p. 252. 



