326 



NATURAL HISTORY OF ARTHROPODS. 



Fig. 361. — Saperda 

 tridentata. 



S. vestUa, a species whose larva bores in linden and poplar, is from 0.5 to 0.8 of an 

 inch long, is greenish yellow, with three black spots on the middle of each elytron. The 

 beetles are found about the linden from May to the end of summer ; they eat the 

 bark and petioles of the leaves. In Philadelphia their larvas have been at times so 

 common as to do serious damage to the linden trees by penetrating the wood and 

 undermining the bark. The larvse are slender, of nearly the same breadth from the 

 prothoracic region to the penultimate abdominal segment, and have three pairs of small 

 thoracic feet. iS. tridentata, sometimes called Compsidea tridentata, 

 is from 0.4 to 0.6 of an inch long, dark brown or gray in ground col- 

 oration, with dull red markings, as follows : a curved line behind the 

 eyes, two stripes on the prothorax and a marginal, three-toothed, red 

 stripe on each elytron. The legless larva, which feeds on the elm, 

 is, according to Prof. A. S. Packard, "a little flattened, with the 

 lateral fold of the body rather prominent ; end of the body flattened, 

 obtuse, and nearly as wide as at the first abdominal ring." The pro- 

 thoracic segment is wider than the rest of the larva. The whole larva is covered with 

 scattered hairs. Oviposition takes place in June ; the larv£e, after channelling beneath 

 the bark, and furrowing the surface of the wood during one or more years, pupate in 

 the spring. Not only do these insects attack dead trees, but they prove very destruc- 

 tive to living elms. In some cases the death of elms has been attributed to- leakage of 

 illuminating gas from the street mains, when in reality the cause of death 

 was the boring of this destructive beetle. S. lateralis, which somewhat 

 resembles S. tridentata, but in which the lateral line does not have three 

 teeth, also mines the inner bark of elms. Its larva is similar to that of 

 S. tridentata. Of other American species, S. mcesta, S. calcarata, 8. 

 concolor attack poplars. The last sjiecies is gray, with darker antennae. 

 S. calcarata is a large gray species, irregularly striped and spotted with 

 yellow; it is sometimes 1.25 inches long. Its elytra end in a spur, 

 whence its specific name. S. moesta, a black species, about 0.35 of an 

 inch long, is the only North American sfiecies found on the_ Pacific 

 slope, being distributed from Canada to Oregon. In Europe two com- 

 mon species, both living on species of poplar, are *S'. carcharias and S. 

 populinea. S. populinea is about 0.5 of an inch long, S. carcharias about 

 double as long. The male of the latter species is grayish yellow, the 

 female is ochre yellow. S. populinea is greenish or yellowish gray, with three longitudi- 

 nal yellow lines on the prothorax and a longitudinal row of yellow spots upon each 

 elytron. 



Differing from the species of Saperda, in having cleft or appendiculate claws, are 

 the species of the genera Oberea, Tetraop)es, and Phytcecia. The species of Oberea 

 are very slender, nearly cylindrical, and have the episterna of the metathorax wide, the 

 epipleurae distinct, and the claws broadly appendiculate. 0. tripunctata, a species 

 about 0.5 of an inch long, feeds as larva upon the stems of the raspberry. The beetle 

 is black, with a yellow prothorax, on which are three black dots arranged in a triangle. 

 It girdles the raspberry twigs in which it lays its eggs, probably in order to check the 

 growth of the plant. 



Tetraopes has a less slender form than Oberea, the claws are cleft, the eyes broadly 

 divided, the prothorax dilated at the sides ; the species are all bright red, marked with 

 black spots, and all feed upon milkweed {Asclepias). The larvae probably devour the 



Fig. 362.— Larva 

 of Saperda cal- 

 carata. 



