148 NATURAL HISTORY 



The insect that infests turnips and many crops in 

 the garden (destroying often whole fields while in their 

 seedling leaves) is an animal that wants to be better 

 known. The country people here call it the turnip-fly 

 and black dolphin ; but I know it to be one of the 

 Coleoptera ; the " Chrysornela oleracea, saltatoria, femo- 

 ribus posticis crassissimis." In very hot summers they 

 abound to an amazing degree, and as you walk in a field 

 or in a garden, make a pattering like rain, by jumping 

 on the leaves of the turnips or cabbages \ 



by taking their tail in their mouth and letting it go suddenly. When it 

 prepares to leap, our larva first erects itself upon its anus, and then 

 bending itself into a circle by bringing its head to its tail, it pushes forth 

 its unguiform mandibles, and fixes them in two cavities in its anal 

 tubercles. All being thus prepared, it next contracts its body into an 

 oblong, so that the two halves are parallel to each other. This done, it 

 lets go its hold with so violent a jerk that the sound produced by its 

 mandibles may be readily heard, and the leap takes place. Swainmerdam 

 saw one, whose length did not exceed the fourth part of an inch, jump in 

 this manner out of a box six inches deep; which is as if a man six feet 

 high should raise himself in the air by jumping one hundred and forty- 

 four feet ! He had seen others leap a great deal higher." E. T. B. 



3 In this work of destruction, although a share is taken by the Hnlticn 

 oleracea, GEOFFR. (Chrysomela olei'acea, LINN.) the most powerful agent is 

 the Halt, nemorum, a still smaller beetle, about the twelfth part of an inch 

 in length, black above, and having a yellowish stripe along the middle of 

 each of its wing-cases. The injury inflicted on the turnip crops by these 

 pigmy depredators is in some years immense: it has been calculated tlutt 

 in Devonshire alone, in 1786, the damage inflicted by them on the a^ri< nl- 

 turist amounted to not less than one hundred thousand pounds. The 

 turnip-fly, or turnip-flea (as Messrs. Kirby and Spence propose to rail it, 

 not from its entomological affinities, but from its diminutive size and 

 leaping powers J is the earliest enemy of the turnip crops. The instant 

 that the plant appears above the ground, it is attacked by the little 

 insect which destroys the seedling or smooth leaves, and the plant 

 perishes in consequence. After the rough leaf has made its appearance, 

 the crop may generally be regarded as safe from severe injury from this 

 cause. This is the more fortunate, as the turnip-fly is always active 

 during the summer, and is ever at hand prepared by regaling itself on its 

 favourite food to ruin the hopes of the farmer. Rapid growth of the 

 crop (and to secure rapid growth good cultivation and suitable manure 

 are the effectual means,) is the most natural way of preserving it : while 

 it is in the smooth leaf it is in jeopardy ; when in the rough leaf its 

 danger from this enemy may be looked upon as escaped. 



But although the turnip may have assumed the rough leaf, and have 



