106 



THE AGRICULTURAL NEWS. 



Ai'KiL 2, 1910. 



INSECT NOTES. 



LADY-BIRDS AND WEEVIL BORERS. 



The lady-birds and weevils belong to two groups of tli"! 

 beetles, 01- Coleoptera ; the lady-birds to tlie family Coccinel- 

 lidae, and the weevils to the sub-order Rhyncophora. They 

 are very distinct in appearance, as well as in habit, and the' 

 members of one group can easily be told from those of the 

 other. 



The weevils (Rhyncophora) have the head prolonged into 

 a beak or snout, and from this peculiar structure they have 

 been called the snout beetles or bill-bugs. In the case of 

 some of the weevils, the snout is long and slender, and in 

 others short and broad. In all cases the mandibles are 

 .situated at the tip of the l.ieak. The lady-birds (Coccinellidae) 

 are generally rather hemispherical in shape, the wing-covers 

 being much curved and rounded; the head is very small, and 

 the thorax is much smaller than the abdomen, though larger 

 than the head. 



Fig. 1.3 shows two lady-birds, (a) the 

 spotted lady-bird, 2Iegilla maculata, and 

 (b) the red lady-bird, Cydoneda mn- 

 ijuinea. Megilld maculata is slightly 

 elongated, pinkish red in colour, with 

 black spots, and rather flat. The red lady- 

 bird is much more hemispherical; the 

 small head and thorax are black, the thorax 

 with a whitish marking; the arched and 

 rounded wing-covers are blood-red. 



These are common insects in the AVest Fig. 13. 



them worthy of notice on the part of the agriculturist, 

 and he should distinguii-h them at sight from all other 

 insects. There are several species found commonly in 

 the West Indies, and in ever}- country there are indigenous 

 ones which prey on the native forms of scales and plant 

 lice, generally kee[iing them in check, except for occasional 

 outbreaks. An interesting and valuable example of this is 

 to be found in the case of an Australian scale insect and its 

 associated lady-bird. The scale insect — the fluted scale 

 (Iceri/a jnnrhasi) — was introduced into California about 

 186.5. By the year 1886, it had become a most serious pest 

 of oranges. In 1889, the natural lady-bird enemy (Kovius 

 cardinalis) of this scale was imported from Australia into 

 California; in a very short time it brought the (luted scale under 

 complete control, and for a number of years has prevented 

 the scale from developing in sufficient numbers to become 

 a serious pest. 



The weevils (Rhyncophora) are very different in structure 

 and in habit from the Coccinellidae. They are all plant 

 feeders, and some of them are among the worst enemies 

 of cultivated plants. 



Two serious pests belonging to this 

 group are borers of sugar-cane — the root 

 borer {Diaprepea alihrci'iatus — A(/ri- 

 cultural A'c«'6-, Vol. IX, p. .58, Fig. 7) and the 

 weevil borer {Splienopliorus sericcus — Agri- 

 ctdtural Xews, Vol. IX, p. 58, Fig. 6). The 

 larva of the former of these lives in the 

 underground portion of the cane, while that 

 of the latter is found in the stem above 

 ground. In the West Indies, the mistake 



>fCl! 



tr 



. c 



(a) Meijilla maculata. 

 Indies, and ought to be well known to (b) Cydoneda sangtiinea. (c) Egos of is made of calling one or both of these 

 every agriculturist. They are often to L.vdy-bied. pests ' lady-birds'. This leads to great 



be found in fields of cotton, corn and 

 potatos, and .sometimes in cane-fields. They also occur in 

 lirre trees, pigeon peas and, in fact, on any trees or plants 

 infested by plant lice, scales and similar insects. These 



misunderstanding, for only the beneficial 

 insects of the family Coccinellidae should be known as 

 ladybirds. In all other parts of the world where English is 

 spoken, this is the custom; and it is convenient to be able to 



make use of the 

 with general usage, 

 before now, that 

 appeared in the 

 have been misun- 

 in the West Indies, 

 thought that the 

 was used in con- 

 that they know to 

 Every reader of 

 JVews ought to 

 never to apply the 



Fig. 14. L.a^ce Wing and Lady-bied. (a) Eggs, (b) 

 Larva of Lace Wing; (c) Larva of Lady-bird. 



two lady-birds are not active enemies of scale insects, although 

 tho.y feed upon them to some extent. The most energetic lady- 

 bird enemies of scale insects are verj- small. There will 

 often be found, on scale-infested limes and guavas, 

 dark blue, brownish, or blackish lady-birds about " 

 the size of a pin's head. These are very 

 active, and if watched carefully, may be seen 

 to capture and devour the young of scale insects, 

 and even to force their way under the scale-cover- 

 ing of the adult in order to get at the insect 

 itself. The larva of a lady-bird is shown at Fig. U 

 (c), and the eggs are represented at Fig. 13 (c). 

 The family Coccinellidae includes, with very 

 few exceptions, beneficial insects. Their habit 

 of feeding exclu.sively on the worst kinds of insect Pio. 16. Root Bo 



term in accordance 

 It has happened, 

 articles which have 

 A(jricuhural Xeim 

 derstood by readers 

 because they have 

 word' lady-bird ' 

 nexion with insects 

 be injurious, 

 the Agricultural 

 m a k e an effort 

 name lady- bird to 

 those ^\hich,as has 

 jilained, have the 

 otherinsects. Atthe 



any insect except Fig. 15. Weevil Boe- 

 been already ex- er of Stgae-cane. 

 habit of feeding on 



same tiuie it will be of great value if all the insects which 



have the front of the head jirolonged into a snout or beak 



could be spoken of, and thought of, as weevils, and the 



term weevil could always be made to mean 



a serious, or at least troublesome, pest. 



Two weevils of ordinary occurrence in these 

 islands have already been mentioned and are figured 

 on this page. The granary and rice weevils, which 

 infest stored grains and food stufl's, figured in the 

 Agricultural ^V ('(/■>■, Vol. I, \, p. 26, Figs. 4 (a) and (d), 

 are also of common occurrence in the West Indies. 

 The fiddler beetle (Pracpodcs vittatus) is 

 a weevil, the larva of which is a serious pest of 

 orange trees in .Tamaica, where it attacks the 

 roots and causes the death of the tree. The 



pests— .scale insects and plant lice— renders (Dkiprepes ahhrenatm.) orange root grub of I'orto Rico is Diaprepes 



