344 



NATURAL HISTORY OF ARTHROPODS. 



Ithycerus noveboracensis is a gray weevil, dotted witli lil:u-l<, and lias a yellow 

 scutelhira; its auteniine are straight, not geniculate; its length is about 0.5 of aii inch. 

 Although the larva' breed in the tender twigs of bur-oak (Quercus ma- 

 croccaya), the adult beetles eat the tender shoots and bark of the apple. 

 It is found from Canada to Texas. 



In the United States JBrurhus pifii, of the Bruehida', is generally 



termed the pea-weevil, but in England >'iifones lineatus, the mystery 



of whose life history has been lately solved by Mr. T. H. Hart, is the 



Imisnoveboi-cC- pea-weevil. It is a brownish-gray beetle, rather slender, and only about 



'^"""' 0.15 of an inch long. As imago it has been long known to eat the 



leaves and stems of beans, peas, and other leguminous jilants, often totally ruining 



fields of young peas ; lately tlie hirvs have been discovered to attack the roots of 



the same plants. 



The weevils of the sub-family Otiorhynchina; differ from those of the Cureulion- 

 inoe in having mandibles that are provided in the pupal state with a piece which is 

 regularly deciduous in the early part of the imagn state, and which, consequently, 

 leaves a scar upon the mandibles. 



Many species of Otiorhynchinaj are beautifully ornamented with scales. The most 

 brilliant s]iecies lielong to the South American genera J^ordups and Entimus. E. 

 iinjjerialis, the diamond-beetle, is from 1 to 1.25 inches long, really of a black ground 

 color, but its surface is deeply ])unctate, and the jiunctures 

 are lined with bi-illiant scales, the jiredoniinant color of 

 which, as seen against the black background, is bright green. 

 These scales are so numerous that the beetle a]ipears green 

 instead of black. If some of these scales be scraped off with 

 a fine-pointed knife and examined under the microscope, 

 most of them will be found to be oval, about O.OOG of an 

 inch long; by transmitted light the scales are red, blue, and 

 yellow, — chiefly red ; by reflected light they have colors 

 complimentary to those seen by transmitted light, conse- 

 cpiently nrostly green, thus ex]>laining why the scales on the 

 black background furnished by the beetle appear green. 

 The peculiar, changeable nature of the colors indicates that 

 the coloration of these scales may be only optical, not i>ro- 

 duced by pigment within them. That the color is produced by interference of lumin- 

 ous waves is easily shown l)y putting a drop of chloroform on the scales upon a micro- 

 scope-slide, when the colors will vanish only to reapjjear when the chloroform has 

 eYa])orated, an experiment that may be repeated an indefinite number of tiiiH's with 

 the same scales. 



Arandgusi fullcrL an ii\al lihick weevil, lightly covered with ilark brown scales, 

 and about 0.25 of an ini'h long, does much chunage, both as lar\ a and imago, to roses 

 in greenhouses. The larvte devour the roots; the imagos disfigure the leaves and 

 flowers, and even eat into the nnopened buds. This species is distributed from New 

 England to California, and in the hitter locality attacks several kinds of out-dooi- 

 shrubs. 



The suli-family Attelabinre includes weevils which have the abdomen alike in the 

 male and female, the elytra without lateral fold on their innei' surface, the labium 

 wanting, and the mandibles stout and pincer-shaped. 



Fig. 380. — Entimus iwj/tnalis 



