THE LOCUST TREE BORER. 357 



species. He gives, however, some interesting facts in the Practical 

 Entomologist, vol. i, p. 29, regarding the appearance of this insect in 

 the Western States, as follows : 



The history of this species is very curious, aud as it has only recently been eluci- 

 dated by myself, aud some additional details cau now be added, may be briefly summed 

 up as follows: About a hundred years ago this insect was well known to Forster to 

 inhabit the locust in the State of New York. Twenty years ago, although the best 

 Illinois botanists agree that the locust grows wild in the southern part of Illinois, it 

 was still unknown in that State. Shortly afterwards it commenced attacking the 

 locusts in the neighborhood of Chicago, and thence spread gradually in a south-south- 

 west and west direction through the State, sweeping the locusts before it wherever 

 it came. In 1860 it had pretty well destroyed all these trees in central Illinois. 

 Rock Island lies on the Mississippi River 180 miles south of west from Chicago. In 

 1862 it had reached a point 20 miles east of Rock Island. In 1863 it burst forth sud- 

 denly in great swarms from all the locusts in Rock Island, and the two following 

 years about completed their destruction. It has now (1865) crossed the river into 

 Iowa, and no doubt will continue its travels westward as long as it finds any locust 

 trees to prey on.* 



Lest it should be supposed that, agreeably to the belief of all the older writers, the 

 species that inhabit the hickory is identical with that which inhabits the locust, it is 

 proper to add here, that I myself split the hickory insect out of a stick of hickory 

 wood as much as eight years ago in Rock Island; that abundance of hickory grows 

 in the woods within half a mile of that city, and yet that our locust trees were never 

 •attacked by borers until 1863, when they were suddenly attacked in the manner men- 

 tioned above. Professor Sheldon, of Davenport, Iowa, has also repeatedly, for many 

 years before 1863, split the hickory insect out of hickory wood in Davenport, although, 

 so far as he is aware, the locusts in Davenport had not been attacked by borers up 

 to 1863. Now. if the hickory borer is identical with the locust borer, why did it not 

 attack the locusts in Rock Island and Davenport before 1863 and 1864 ? And why, 

 when it did attack them, did it appear suddenly in great swarms ? 



The larva is six or seven-tenths of an inch long, somewhat flattened, club-shaped, 

 the thoracic segments being considerably broader than the abdominal ones, but at 

 the same time distinctly flattened above and below. Tlie head when extracted from 

 the thorax appears almost circular and narrower than the prothorax. The latter is 

 twice broader than long, rounded anteriorly, flattened above and below, brownish 

 yellow, covered, especially on the sides and below, with a short golden pubescence. 

 A deep, longitudinal sinuated furrow is visible on each side, a short transverse fur- 

 row crosses its posterior end. The upper disk is inclosed between two furrows 

 beginning at the posterior margin, and not reaching the anterior one; a transverse 

 furrow, parallel to the posterior margin, separates a narrow fleshy fold. The ante- 

 rior portion of this upper disk is irregularly punctured and wrinkled, although shin- 

 ing; in some specimens it has an indistinct, elongated, somewhat oblique brownish 

 spot on each side, about the middle; the posterior portion of the disk is opaque, 

 covered with dense longitudinal wrinkles, among which a straight impressed line is 

 a,pparent in the middle. The ventral side is irregularly punctured on the sides, and 

 lias a depression in the middle which is less apparent in some specimens. 



The other two thoracic as well as the two first abdominal segments have, above 

 and below, a transverse flattened opaque disk, limited on each side by a furrow, and 



*Mr. R. V. Rogers, jr., in the Canadian Entomologist for August, 1880, p. 151, re- 

 ports that this beetle was first observed in Montreal in 1855. "In 1862 it was very 

 destructive to the locust trees around Toronto; in 1873 Mr. E. B. Reed saw it in 

 •enormous numbers in London, Ontario, Now it seems to be quite at home in all 

 parts of Ontario." 



