234 



THE AMERICAl^ ENTOMOLOGIST. 



Color— Whitish 



orauffe roots. 



[Fig 173 ] the end of June, and the per- 

 fect beetle appears in ahout 

 three weeks afterwards. 



From what has been said 

 above, it is quite certain that 

 the Broad -necked Prionus 

 bores in the larva state indis- 

 criminately in the roots of 

 grape-vine and apple, and no 

 doubt also in those of the 

 closely allied pear. According 

 to Harris, it also infests the 

 roots of diflferent kinds of pop- 

 lar, and specimens received by 

 us from Kansas inhabited Osage 

 May it not, however, be pos- 

 sible that the larvie found in New Jersey 

 in old rotten oak stumps by A. J. H., of 

 Vineland, N. J., and in oak stumps in Ken- 

 tucky by Mr. Bolter, belonged, not to this 

 species, but to the Cylindrical Orthosoma which 

 we have sketched above (Fig. 170) , and which 

 we have ourselves actually bred from decaying 

 pinewood? As a general rule, to which at 

 present we do not remember a single exception, 

 the larvas of the Long-horned Boring Beetles 

 either inhabit green and living wood or else 

 decaying and dead wood, the same species never 

 attacking both kinds of wood indiscriminately; 

 and we know that the larva of the Cylindrical 

 Orthosoma so closely resembles that of the 

 Broad-necked Prionus, that A. J. M. as well as 

 ourselves might possibly have confounded the 

 two together. At all events, it is quite certain 

 that the Cylindrical Orthosoma must thrive 

 upon other kinds of timber besides pine ; for we 

 found this species very abiindant in 1861 in 

 Union county. South Illinois, where there are 

 no pine trees growing, and where at that period 

 the so-called "poplar " or whitewood was uni- 

 versally used in buildings in place of pine im- 

 ported from the North. To sum up the whole 

 in few words, until larvas found in decaying oak 

 wood are bred to maturity, we cannot be certain 

 that they will produce the same beetle that in- 

 fests living grape-vines and living pear and 

 apple trees. And unless this be so, there is no 

 danger to be apprehended from growing grape- 

 vines and fruit trees among decaying oak 

 stumps. 



Little can be done in the way of extirpating 

 these underground borers, when, as in the 

 present instance, their presence is only indi- 

 cated by the approaching death of the vine. 

 Still, every vine-grower should make it a rule to 

 search for them whenever he finds vines sud- 

 denly dying from any unknown cause, .and 



upon finding such a borer should at once 

 put an end to his existence. The beetle, which 

 may often be found during the summer and 

 fall months, and which not unfrequently rushes 

 with heavy, noisy fiight into our lighted 

 rooms, should also be ruthlessly sacrificed 

 whenever met with. In order to be on the safe 

 side, we also advise not to plant a vineyard on 

 land covered with old oak stumps, and not to 

 use oak stakes where those of cedar can be had 

 as cojiveniently. Whether, in reality, the vine- 

 grower will run any risk by not following this 

 advice, depends upon the considerations enu- 

 merated in the preceding paragraph. 



INSECTS INFESTING THE SWEET-POTATO. 

 Tortoise-heetles, 



(Gassidm.) 

 [Fig. 174.] 



Colors— (2) dirty-cream; (3) l)ro\vii; (4) black and yellow. 



The insects which attack the Sweet-potato 

 plant are few in species, and belong almost en- 

 tirely to that group of beetles popularly known 

 as Tortoise-beetles. With the exception of the 

 Cucumber Flea-beetle {Haltica cucumeris, 

 Harr.), figured and described on page 27, and a 

 few solitary caterpillars, we have never found 

 any other insects on this plant; but we regret 

 to say that these Tortoise-beetles are of them- 

 selves sufficiently numerous in individuals and 

 species to often entirely destroy whole fields of 

 this esculent, and they are especially severe on 

 the plants wheu newly transferred from the 

 hot-bed. 



These insects are at pi-esent included in the 

 great Chrysomela family of beetles, though 

 they were formerly placed in a separate family 

 (Cassimd^) by themselves, and there certainly 

 are few groups more strongly characterized. 

 They are almost all of a broad sub-depressed 

 form, eitheroval or orbicular, with the thoraxand 

 wing-covers so thoroughly dilated at the sides 

 into a broad and flat margin, as to forcibly recall 

 the appearance of a turtle, whence the popular 

 name. Many have the singular power, in a 

 greater or less degree, of changing their color 

 when alive, and as we shall show further on, 

 some of them shine at will with the most bril- 

 liant metallic tints. 



