ARTICULATA. 141 



butterfly, Acherontia atropos {j>l. 80, fig. 15), produces a plaintive cry, 

 which is said to proceed from the head. We have discovered that a sound 

 is made by an American species of Lithosia (anotlier nocturnal lepidm^ter) 

 by vibrating the sides of the thorax ; and we have heard a very low and 

 dull musical sound fr(,)m the hemipterous genus Belostoma {pi. 80, fig 71), 

 produced apparently by a vil^ration within the thorax, and from the low- 

 ness of the note produced, a large portion of the organs must be concerned 

 in producing it. 



The relations of insects to man are more numerous and important than 

 those of the other classes of animals excepting the domestic breeds, and 

 they exceed these in the importance of their histor3\ Almost every year 

 new enemies to tlie various vegetable productions cultivated by the farmer 

 and gardener make their appearance, the history of which must in many 

 cases be known before the proper means can be taken to prevent their 

 increase. Often the noxious insect has a destroyer in some other insect, 

 and the latter, being seen about the infested vegetable, is often mistaken for 

 the real enem3\ Some insects destroy the leaves and blossoms of plants, 

 as the larvae of butterflies ; the larvae of some Coleoptera., especially those 

 of some of the beetles {jjl. 81, fig. 130), are very destructive to the roots 

 of grass, which they sometimes destroy to such an extent tliat the sod can 

 be taken up in large flakes. An instance is related of a ftirmer whose crops 

 were entirely destroyed by the larvse of Melolontha {2)1. 81, fig. 130), of 

 which eighty bushels were collected. At one time the cultivation of the 

 sugar cane had to be abandoned on account of the increase of an ant 

 {Formica saccharivora)^ which destroyed all the plantations ; and on the 

 eastern continent large tracts are sometimes rendered desolate by the 

 ravages of the large grasshopper, Locusta migratoria. The Carculionidce 

 (including the weevils) {jyl. Si, figs. 67-76) are destructive to various kinds 

 of grain and seed; the Ceramhyc'idus, {pi. 81, fig. 50, &c.) destroy growing 

 and dead wood ; JBostricJius, &c., perforate the bark ; and the Aphides and 

 other families suck the sap ; so that amongst the various orders, all parts of 

 a plant, from the root to the seed, whether living or dead, are subject to 

 destruction. 



Insects are frequently useful to plants in bringing the pollen to the 

 pistils, and thus securing the continuance of the species in cases where 

 this could not be eftected except by such extraneous means. The insects 

 which feed upon honey and pollen effect this object, not only in cases where 

 the stamens and pistils, although together, present difiiculties in the mode 

 of getting the pollen to the latter, but in those cases where the plants are 

 dioicous, when it sometimes happens that the staminate and pistillate flowers 

 are several miles apart. Moreover, the stamens and pistils often arrive at 

 maturity at different periods in the same blossom, so that the v\])Q pollen is 

 carried upon the liairy body and limbs of the insect to the mature pistils of 

 a different tree. 



The predaceous insects are useful in destroying those which feed upon 

 vegetables, and they attack both the perfect insects and their larvae. The 

 parasitic families destroy an immense number of caterpillars, and the larvae 



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