930 MS HABDT ON INSECTS • 



of a Northumbrian fanner on this Bubjeot, I givo verbatim from i\ie New- 

 castle Journal (or Aug. 5, 1780: — "A correspondent desires the public to 

 take immediate notice of the following remedy for the present alarming at- 

 tack upon turnips by caterpillars. An acquaintance of his having such pro- 

 digious numbers as to threaten the total destruction of a very forward close 

 ^inclosuro) of turnips, put him upon thinking of a ready method to «le- 

 stroy them; when luckily ho advised him to make use of the following 

 scheme: to procure as many ducks or other fowls as he possibly could, 

 and keep them in the close in the day time; which having done, and water 

 in small vessels [having been] carried forward for them as they proceeded in 

 their work; in three day's time, to his great astonishment, the whole close 

 WJis entirely cleared of these formidable foes, though he had only about GO 

 in the first day, 100 the other two ; and though the close was five acres, and 

 had, upon an average, half a score of caterpillars on each plant." 



6. ORUBs OF Two-wiNGEB FLIES (Dlptera). 



I am not aware of any complaints of damage occasioned by what is com- 

 monly called " the grub," or the larva of the long-legged spinner fly (Tipu- 

 ia oleracea,&c.),tothe turnip crop in Berwickshire, although other crops are 

 often rapidly cut down by it. I notice, however, that in the isle of Angle- 

 sey, it was very hurtful to turnips in 1845.* It is partial to stiff, wet soils ; 

 and there is a probability that the extension of drainage will either extir- 

 pate it, or, at least, greatly modify its numbers. 



I find that the leaves of many turnips, when full grown, are occasionally 

 undermined by the larva of a two- winged fly,t which agrees pretty closely, 

 but does not coincide, with the description of that of Anthomyia Brassicm of 

 Bouche, so destructive to plants of the cabbage tribe, by eating passages 

 into the roots and stems, which cause them to rot.J Minute yellow and pink 

 grubs of some small gnats (iVfa2o6ri .^) are likewise fouud in a similar situa- 

 tion, when the leaves begin to decay. 



7. APHIOES, OK PLANT tlOE. 



The last insects to which I shall call attention, are the Aphides, or Plant 

 Lioe. Their wonderful history, extraordinary mode of propagation, im- 

 mense numbers, and the loathsome appearance they give to tho vegetables 

 on which they swarm, I can do little more than allude to. During the early 

 part of the season, the females hatched from eggs laid in the preceding 

 autumn, go on to produce generation after generation of which the mem- 

 bers in their turn are equally prolific, without meeting with the male. 

 The males appear in the autumn ; when females differently organized from 

 the foregoing generations are likewise produced, which lay c^gs destined to 

 preserve a race for the future year. A single individual, according to Reau- 

 mur, will, in 5 generations, be the progenitor of 5,904,900,000 descend- 

 ants; and 10 (Mr Smee says 20) generations may exist in a year; an 

 amount of fecundity almost transcending belief. The female is either wing- 

 less or winged. In the latter case, when at certain periods of the season, 

 a restless desire of change is impressed upon the race, whether wingless or 

 winged, the insects leave their original plants, and betake themselves in 

 immense swarms to other districts, to settle on a kind of food, often totally 

 differeut from, that they have deserted ; while those not similarly equipped 

 become, in many instances, indiscriminate in their taste, and fall upon almost 

 all kinds of herbage. The Aphis is oblong, conical, oval, or flask-shaped ; 

 has a soft and pulpy body ; and may be readily crushed. Its head is fur- 

 wished with a pair of long slender horns (antennae) which are reflected in 

 a state of repose, but in walking are directed forwards, and applied alter- 

 oately to eitner side, to pilot its way. Its six legs are slender and long; 



* Gardeners' Chronicle, 1845, 480. f See note E. 



\ Konar on Injurious Insects, 159, 160. Tliig appears to be the Musea radicura of 

 fiinn. Syst. Nat., ii., 992. Antliomyia radicum, Meiffon, Burop. Zweiflug. Inselitea, v., 

 168. Macquort (8tfii«s ft *iuffua,} Dipteres, ii., 341. 



