405 



son, Xaturg. Ins. Deutsch., vol. yi, p. 865), a well-known European 

 species, originally described by Koch m 1803 (Ent. Heft, vol. ii, p. 75) 

 as Haltica annorackv, after its food-plant, the liorse-radish, Xasturtium 

 [Cochlea ria) armoracia. It is j)robable that the plant on which the few- 

 s])ecimens taken were observed was the horse-radish, although it was 

 thought at the time to be Eumex. All of the Phyllotretas, so far as 

 we know, breed on cruciferous plants, and the occurrence of these 

 specimens on the supposed dock was regarded as purely accidental, 

 is'ot more than a handful of the plants were seen, and these were in 

 the midst of the true Eumex. 



In appearance this Ph3dlotreta is quite distinct from any species 

 belonging to our fauna, hence it is i^ractically certaiu that it is of 

 recent introduction. Most introduced species first obtain a foothold 

 near the seaport where first imported, and from this point gradually 

 extend inland. In this instance the introduction appears to have 

 begun right iu the heart of our country. 

 It might have been imported witli horse 

 radish, or with some potted ornamental 

 Xasturtium, and it is not impossible that 

 these plants were brought to this country 

 expressly on account of, if not for exhibi- 

 tion at, the Columbian Exposition. It is 

 more probable, however, that they were 

 introduced at a somewliat earlier date. 



In its native home this flea-beetle ranges 

 through middle Europe. Mr. Schwarz has 

 a series from Guttenberg, Iowa, collected 

 in some numbers last year on horse-radish 

 by Mr. Hugo Soltau. Guttenberg is on the 

 Mississippi Eiver, about 200 miles from 

 Chicago. From the close proximity of other 

 States to these points, it may be inferred 

 that the species has already invaded Wisconsin and Indiana, and we 

 shall expect soon to see this insect spread to Missouri and other States 

 that border on the Mississippi below Iowa and perhaps also to southern 

 Minnesota and Michigan. 



Another Euroi)ean food-plant of Ph. armoracia', viz, Xasfurtium 

 palustre, or marsh cress, has been introduced in this country, but it is 

 hardly probable that the insect will restrict itself to these plants, but 

 will in time, as it becomes more at home in its new surroundings, 

 gradually extend its list of food-plants as it extends its distribution. 



In Europe Pit. nemorum, the turnip flea-beetle, and in the United 

 States the striped or cabbage flea-beetle, Ph. vittata, do much damage 

 tocruciferous crops. Ph. .sinuata, common to Europe and Xorth America, 

 has similar habits, but has not yet attracted much attention by its rav- 

 ages. The last two species have been treated at length in the Annual 

 IS.JOl— Xo. 5 -l 



Fig. 4:7.—Phijllotreta armoracice: fe- 

 male — much enlarged (origiual). 



