324 



NATURAL HISTORY OF ARTHROPODS. 



rarely knobbed ; they are inserted in various ways, and generally have eleven joints 

 sometimes more, rarely fewer ; they are often much better developed in the males than 

 in the females. The elytra usually cover the entire abdomen ; a few genera, however, 

 have very short elytra. The wings are absent in a few species, and the elytra connate. 

 The mandibles are very stout, but of variable forms. The species are often beautifully 

 colored, metallic or velvety, and are oftentimes of considerable size, the Cerambycida? 

 probably containing the longest species of beetles. Many longicorns are more or less 

 spiny, some species closely resembling twigs, and, according to Mr. H. W. Bates, 

 ^Ethomerus lacordairei, a Brazilian species, mimics a butterfly's pupa grown over with 

 fungus. A curious habit of Megaderus bifasciatus, a species found in Texas, is to eat 

 out the printed portions of posters. Certain species are odorous, those of Prionus 

 using their odor as a sexual attraction. Callichroma moschata, a large European spe- 

 cies, derives its specific name from the pleasant musky odor which it exhales, and which 

 is noticeable at considerable distance from the insect. Sonorific organs are possessed 

 by nearly all, probably by all, species of Cerambycida?. 



The eggs are laid in crevices of bark and of wood ; the larva? feed in both living 

 and decayed wood. The females of a few species girdle twigs and lay their eggs in 

 the portion beyond the girdling ; the twigs thus girdled die and are broken off by 

 winds, thus furnishing fresh but dead wood for the larva?. The females of certain 

 species are said to cut off or girdle twigs by seizing them in their mandibles and flying 

 rapidly around the twig as a centre ; this mode of girdling is exceptional, if practised 

 by any species, since longicorns mostly girdle twigs while resting on the branch below 

 the point to be girdled. Some species lay a large number of eggs ; Prionus laticollis 

 has been found, upon dissection, to contain from three hundred to six hundred eggs. 

 The metamorphoses of some species of longicorns are supposed to require as long as 

 twenty years, but if this is the case it is exceptional, for many species attain full 

 growth in from one to three years. 



The larva? of Cerambycida? are long, cylindrical, or flattened whitish 

 grubs, with distinct labial palpi, elliptical or circular stigmata, and 

 Y-shaped anal opening. They bore, for the most part, in woody por- 

 tions of trees ; some, however, attack herbaceous plants. The head of 

 the larva? is partly retractile into the first thoracic segment, the an- 

 tennas are very small and concealed in a fold of the head, ocelli are 

 usually absent. The larva? are mostly legless, and when legs are present 

 they are small, with only one claw ; but the larvae assist their peristaltic 

 motion through their mines by means of wart-like processes upon their 

 dorsal and ventral surfaces. The form and mode of plication of these 

 processes are of importance in distinguishing the species of longicorn 

 larva?. Most of the damage done by these larva? is in destroying timber 

 or by killing shade trees, no less than a dozen different species being 

 known to attack hickory. In Europe damage is said to have been done 

 to grain by the larva? of longicorns boring in the ears, and to vegetables 

 such as carrots. The fleshy larva? of Macrotoma corticinum, cooked 

 with rice, are eaten b\ r natives of Madagascar ; and the natives about 



FJG. 359. Larva ,,. , . . , , . 



of Monoham- King George s Sound, in West Australia, eat both larva? and images 



of Bardlstus cibarius. 



Cerambycida? are among the more difficult beetles to classify satisfactorily, because 

 structural characters, which are usually generic, often become only of specific value in 



