844 



NATURAL HISTORY OF ARTHROPODS. 



FIG. 385. nil n- 

 cerus novebora- 

 censis. 



Ithyceriis noveboracensis is a gray weevil, dotted with black, and has a yellow 

 scutellum ; its antennas are straight, not geniculate ; its length is about 0.5 of an inch. 

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

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

 It is found from Canada to Texas. 



In the United States Bruchus pisi, of the Bruchida?, is generally 

 termed the pea-weevil, but in England Sitones lineatus, the mystery 

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

 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 plants, often totally ruining 

 fields of young peas ; lately the larva? have been discovered to attack the roots of 

 the same plants. 



The weevils of the sub-family Otiorhynchinae differ from those of the Curculion- 

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

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

 leaves a scar upon the mandibles. 



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

 brilliant species belong to the South American genera Lordops and Entimus. E. 

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

 color, but its surface is deeply punctate, and the punctures 

 are lined with brilliant scales, the predominant color of 

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

 These scales are so numerous that the beetle appears 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 0.006 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- 

 quently mostly green, thus explaining 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 pro-, 

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

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

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

 evaporated, an experiment that may be repeated an indefinite number of times with 

 the same scales. 



Aramigus fulleri) an oval black weevil, lightly covered with dark brown scales, 

 and about 0.25 of an inch long, does much damage, both as larva and imago, to roses 

 in greenhouses. The larvae devour the roots; the images disfigm-e the leaves and 

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

 England to California, and in the latter locality attacks several kinds of out-door 

 shrubs. 



The sub-family Attelabinae includes weevils which have the abdomen alike in the 

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

 wanting, and the mandibles stout and pincer-shaped. 



FIG. 386. Entimus imperialis. 



