302 REPORT OF THE COMMISSIONER OP AGRICULTURE. 



described at length the observations of Mr. H. Le Keux (Trans. Ent. 

 Soc. Lond. IL, 24) upon the closely allied European Haltica nemorum, 

 showing that the larvae ruined the leaves of turnips and allied plants, 

 and pupated under ground. Then, having remarked upon the similar- 

 ity, in appearance between the two species, he goes on to say: " This 

 account will consequently apply to our insect in every respect, it is 

 probable, as exactly as though it was the insect upon which the obser- 

 vations were made." 



The fallacy of this belief was shown by Dr. Shimer (American Nat- 

 uralist, II, 1869, p. 514, and American Entomologist, I, p. 158), who has 

 recorded numerous observations proving that the larva) live under- 

 ground, feeding upon the roots of cruciferous plants. Concerning the 

 damage done by the larva3, he says : 



" Every year the young cabbage plants and turnips in this region 

 (Mount Carroll, Carroll County, Illinois) receive great damage from 

 these larvse, and often when we have dry weather, in the latter part of 

 May and early in June, the cabbage plants are ruined. A large pro- 

 portion of the plants are killed outright in June, and the balance ren- 

 dered scarcely fit for planting, but when the ground is wet to the sur- 

 face all the time, by frequent rains, the young plant is able to defend 

 itself much more effectually by throwing out roots at the surface of the 

 ground when the main or center root is devoured by the larva; but in 

 dry weather these surface roots find no nourishment, and the plant must 

 perish." 



These observations have been confirmed by our own and by those of 

 several of our correspondents, among them Dr. A. W. Hoffmeister, of 

 Fort Madison, Iowa. The case, however, is complicated from the fact 

 that a very closely-allied species (Phyllotreta zimmermanni), which we 

 shall treat of next, is a leaf-miner in the larva state. 



The eggs of the Wavy-striped Flea-beetle, as found upon radishes by 

 Miss Murtfeldt, are deposited two or three together upon the root near 

 the crown, in an irregular excavation gnawed by the perfect beetle. 

 They are very minute and fragile, of an oval form and a translucent 

 white color. The larva (Plate III, Fig. 6, a) is slender, subcylindrical, 

 and tapers at each end. The color is pale yellowish-white, with brown 

 head and anal plate, and with thoracic marks and transverse rows of 

 minute hair-bearing warts, as in the figure. 



REMEDIES. 



The question of remedies is one which has not been very satisfactorily 

 solved, though with care and watchfulness it is possible to keep vege- 

 tables almost entirely free from this flea-beetle. Dr. Fitch details ex- 

 periments with many of the substances recommended, and his conclu- 

 sions, from his own experiments and those of Le Keux and others, are 

 about as follows : 



The beetles pretty generally forsake the plants which have been 

 dusted with lime, plaster, ashes, soot, Scotch snuff, sulphur, or with 

 two or three of these substances mixed. Dry unleached ashes seem to 

 produce the most marked effect in driving away the beetles. "But," 

 Dr. Fitch goes on to say, u although these substances, ashes especially, 

 usually suffice for driving these flea-beetles from the plants, my obser- 

 vations assure me of the fact that a season occasionally arrives when 

 they fail of having any perceptible effect. The insects at times become 

 more bold and fearless than is their common habit. Numbers of them 

 will cling to the leaf, regardless of the dust falling upon them, and 



