58 



THE AGRICULTURAL NEWS. 



February 25, 1905. 



INSECT NOTES. 



strength of Hardbacks. 



In oi-der to contrast more clearly the strength of these 

 insects with the strength of larger animals, the following 

 figures are given, based on the results of experiments 

 (1), (2), and (3) recorded in the Agricultural Nexos (Vol. II, 



In (1) the beetle dragged a load 15-43 times its own 

 weight, in (2) it pushed a weight 141-1 times its own weight, 

 and'in (3) it carried and dragged a load 400 times its own 

 weight. If a man weighing 150 lb. w-ere as strong in 

 proportion he would be able, under conditions similar to 

 those of (1), to drag a load of over 1 ton. Similarly, with 

 (2) he would be able to push a load of over 9 tons, and in 

 the case of (3) to carry and drag a load of over 27 tons. 

 If a horse weighing 1,200 lb. were as strong in proportion 

 as the hardback, it would be able to draw in (1) 8 tons; in 

 (2) 75 tons ; and in (3) it w-ould have to move a load, partly 

 on the ground, of 214 tons. 



Physiologists estimate that a man can draw -86 per cent, 

 of his own weight and a horse only -67 per cent, of its 

 weight. Therefore, a man weighing 150 %. can draw 129 ft., 

 and a horse of 1,200 11). can draw 804 ft. Comparing these 

 figures with the figures given in experiment (2), it will be seen 

 that the beetle is about 164 times stronger than a man and 

 about 211 times stronger than ahorse, in proportion to its 

 weight. 



Moths and Butterflies. 



Moths and liuttertlies belong to the order of insects to 

 which has been given the name of Lepidoptera, which is 

 derived from two f4reek words meaning fcale and wing, and 

 refers to the scales with which the wings of most lepidop- 

 terous insects are covered. These scales are flattened and of 

 many colours, giving rise to some of the most striking colour 

 patterns and colour effects to be found in the insect world. 



The metamorphosis is complete and abrupt. The larva 

 is a caterpillar, with an elongate, more or less cylindrical, 

 segmented body. It is provided with stout mandibles and 

 feeds, generally, on vegetable matter. There are usually three 

 pairs of thoracic legs and five pairs of abdominal legs. 

 Variations occur both in the shape of the larvae and in 

 the number of abdominal legs, and in some species the 

 thoracic legs of the larvae are so reduced as to be scarcely 

 distinguishable and very rarely are entirely wanting. 



The division of Lepidojitera into two great series, 

 Khopalocera, the Hutterfiies, and Heterocera, the Moths, is 

 the most commonly used. The woi-d Rhopalocera is derived 

 from two Creek words meaning chih and liarn, and refers to 

 the clubbed antennae of the butterflies, while the word 

 Heterocera comes from the Creek words meaning other and 

 horn referring to various forms of antennae of the moths. 

 Sharp * gives this classification of the Lepidoptera : — 



' Series I, Hhopahrern or Butterflies. Antennae knobbed 

 at the tip or tliickened a little before the tip, without 



* Cdmhridyi- Nfif}ir(il Hixturij, Insects II, p. 340. 



(lectinatious, projecting processes, or conspicuous arrangements 

 of cilia. Hind wings without a frenulum, but with costal 

 nervures strongly curved at the base. 



'Series II, Heterocera or Moths. Antennae various in 

 form, only rarely knobbed at the tip, and in such cases 

 a frenulum present. In the large majority a frenulum is 

 present, and the costal nervure of the hind wing is either but 

 little arched at the base, or it has a large area lietween it 

 and the front margin ; but in certain families the hind 

 wing is formed much as in the lihopalocera. 



' It may be inferred from these definitions that the 

 distinction between the two sub-orders is neither sharply 

 defined nor of gre-at importance. The club of the antenna 

 of the Fvhoiialocera exhibits considerable variety in form. 

 Butterflies are as a rule diurnal in their activity and moths 

 nocturnal ; but in the trojiies there are numerous Heterocera 

 that are diurnal and many of these resemble butterflies not 

 only ill colour but even in the shape of their wings.' 



Carpenter * says : ' The popular division of Leiiidoptera 

 into Butterflies (lUiopalocera) and Moths (Heterocera) is 

 quite unscientific, the butterflies being more nearly related 

 to the higher moths than these to the lower moths.' Smith t 

 says : ' lihopalocera are those in which the antennae or 

 feelers terminate in a more or less distinct knob or club at 

 the tip, and in which at least the front pair of wings is 

 elevated or vertical when at rest so that the upper surfaces 

 touch when at rest. The Heterocera, on the other hand, 

 have feelers, or antennae, of many difterent kinds, but never 

 in our fauna distinctly clubbed. ' Comstock I makes three 

 divisions of Lepidoptera — the moths, the skiiipers, and the 

 butterflies. Most of the skippers are generally included in 

 the butterfly series, while a few which Comstock ]>laces in this 

 sub-order are classified among the moths by other authors. 



The genus Megath;/miis, which Comstock makes the 

 basis for the family Megathymidae of the skippers, is 

 included by Sharp in the family Castniidae of the moths, of 

 which family Sharp says ; ' The insects of this family 

 combine to a large extent the characters of butterflies and 

 moths. The antennae are knobbed or hooked at the tip, 

 there is a large precostal area to the hind wing. The 

 nervules of the front wings are complex and anastomose so 

 as to form one or more accessory cells.' 



It will be seen from what has been said that the 

 division of Lepidoptera into two great series or sub-orders is 

 merely a matter of convenience, not scientific, and presents no 

 hard and fast line of division, and there is also a question 

 whether, if any sub-orders or series are designated, there 

 ought not to be three divisions. Sharp says : ' The division 

 of all Lepidoptera into two series is merely a temporary 

 device necessitated by imperfect acquaintance with morphol- 

 ogy ' ; and Ckrpoiiter says : ' On the whole, it is better not to 

 adojit any division of the Lepidoptera between the order and 

 the family.' 



The' use of the terms butterfly and moth has, however, 

 become firmly established and will probably continue in use 

 for some time to come, because they are so convenient in 

 their ordinary use and application. 



Fire-flies in Jamaica. The Dai/// Telegraph, 

 February 6, 1905, has an interesting account of the Jamaica 

 fire-flies. They are beetles (Coleoptora) of the familie.s 

 Elateridae and Lampyridae. The writer has proved that 

 fire-flies do not eat mosquitos, as they have been supposed to- 

 do. 



* 7/i,sccf.s .- Their Stnicfirre aiiJ Life. 



t Eeiiiiomic Enfomoliifiii. 



I Maiifial for the Sfwlij of Insecta. 



