242 



(a closely allied species), that, under favorable conditions, some of the grubs become 

 pupje, and even beetles, the fall subsequent to their second spring; but growing 

 torpid on approach of winter, remain in this state in the earth, and do not quit it 

 any sooner than those transformed in spring. On this hypothesis, their being occa- 

 sionally turned up in the fresh beetle state at fall plowing, becomes intelligible. 



Dr. Thomas gives no life history of the grubs in his Entomological 

 Reports, but implies the transformation to the imago in spring in Ihe 

 following words:* "In April, when the ground is being plowed or 

 spaded, often hundreds of them are cast out already in the perfect state, 

 but then they are of a pale, creamy color;" and in an article on these in- 

 sects published in the Farmer's Review of Chicago, for 1881, he expresses 

 the opinion that full-grown larvae destructive that fall will do no further 

 harm, but will transform to the perfect insect the following spring. 



According to Mr. Saunders,t " at the close of the third summer they 

 cease feeding, and bury themselves sometimes 2 feet deep in the earth, 

 and there, in an oval cavity formed by the motions of the larva from 

 side to side, the change to chrysalis takes place, the beetle digging its 

 way through and appearing at the surface in due season, Sometimes 

 the transformation to the beetle state takes place in the fall, for we 

 have several times found fresh specimens at tliis season, showing by 

 their softness that they had but lately escaped from the pupa case. 

 Such perfect insects secrete themselves under ground during winter, 

 and appear with the rest of their troop in spring." 



My own contribution to this history of error was made in 1883 in a 

 brief account of the white grubs as strawberry insects.| " The grubs 

 hatch in the course of a month, and, growing slowly, do not commonly 

 attain full size until the early spring of the third year, when they con- 

 struct an ovoid chamber lined with a gelatinous fluid, change into pupae, 

 and soon after into beetles. Occasionally, however, individuals com- 

 plete their transformation in the ground in autumn, and hibernate in 

 the adult condition, without leaving their pupal cells, until the follow- 

 ing spring." 



General accounts of the life history of the white grub consistent with 

 the conclusions of this paper have been published, without distinction 

 of species or other particulars, by Mr. David L. Bernard, in the Patent 

 Ofiace Report for 1852, and by Prof. G. H. Perkins, in the Second Annual 

 Report of the Vermont Experiment Station (1888). § 



The criticism to be made on most of these statements is substantially 

 that the rule has been regarded as the exception and the exception as 

 the rule. The only white grubs agriculturally destructive which we 



* Sixth Report State Entomologist of Illinois (1876), p. 98. 



t Report of the Entomological Society of Ontario, 1872, p. 18. 



{Thirteenth Report State Entomologist of Illinois, p. 14.5. 



§ Prof. John B. Smith has also noted, in the proceedings of the U. S. National Mu- 

 seum for 1888 (p. 487), the occurrence in October, 1887, of images of Lachnosterna 

 arcuata, already perfectly colored and matured. 



