326 



NATURAL HISTORY OF ARTHROPODS. 



S. vesiita, a species whose larva liores in lindeu 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 arc found about the linden from May to the end of summer ; they eat the 

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

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

 undermining the bark. The larvie are slender, of nearly the same lireadth from the 

 prothoracic region to the penultimate abdominal segment, and have tliree jiairs of .small 

 thoracic feet. S. tridentata, sometimes called Co7npsidea 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 

 /^l |r\ eyes, two stri]ies on the prothorax and a marginal, three-toothed, red 



•f /ip'irv'^ stripe on each elytron. The legless larva, which feeds on the elm, 

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

 ^'"'(ridcmiam'"'" '"teral fold of the body rather iironiincnt; 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 larvre, 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 tliis destructive beetle. S. lateralis, which somewliat 

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

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

 S. tridentata.. Of other American species, *S'. mmsta, /S. calcarata, S. 

 concolor attack poi)lais. The last species is gray, with darker antenna^. 

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

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

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

 inch long, is the only North American species found on the Pacific 

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

 mon species, Ijoth living on species of poplar, are <S'. carcharias and aS. 

 %)opulinea. 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 3'ellow. S. iwindineu is greenish or yellowish gray, with three longitudi- 

 nal yellow lines on the prothora.x. and a longitudinid row of yellow siiots upon each 

 elytron. 



Differing from the species of Superda, in having cleft or appen<liculate claws, are 

 the species of the genera Oberea, Tetraojjes, ami I'/ii/td'cia. The sptecies of Oberea 

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

 ejnpleurie distinct, and the claws broadly appendiculate. O. tripunctata, a species 

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

 is black, W'ith a yellow prothora.x, on which are three black dots arranged in a triangle. 

 It girdles the raspberry twigs in which it lays its eggs, pi-obably in order to check the 

 growth of the [tlant. 



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

 divided, the j)rothorax dilated at the sides ; the species are all bright red, marked with 

 black spots, and all feed upon milkweed (Asclepias). The larvie probably devour the 



Fu). 31)'.;.— Larva 

 of Saptrthi cal- 

 carata. 



