405 
son. Xaturg. Ins. Deutsch.. vol. vi, p. 865), a well-known European 
species, originally described by Koch m 1803 (Ent. Heft, vol. II, p. 15) 
as Haitica armoraeia\ after its food-plant, the horse-radish, Nasturtium 
{Cochlear ia) armoraeia. It is probable that the plant on which the few 
specimens taken were observed was the horse-radish, although it was 
thought at the time to be Rumex. 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. 
Sot more than a handful of the plants were seen, and these were in 
the midst of the true Eumex. 
In appearance this Phyllotreta is quite distinct from any species 
belonging to our fauna, hence it is practically certain 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 in the heart of our country. 
It might have been imported with horse 
radish, or with some potted ornamental 
Nasturtium, 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 somewhat earlier date. 
In its native home this flea-beetle ranges 
through middle Europe. Mr. Schwarz has 
a series from Gnttenberg, 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 European food-plant of Ph. armoraeia; viz. Nasturtium 
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 Ph. nemorum, the turnip flea-beetle, and in the United 
States the striped or cabbage flea-beetle, Ph. vittata, do much damage 
tocruciferous crops. Ph. sinuate, common to Europe and North 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 
18391— No. 5 ± 
Fig. 47.— PhylbAreta armoracice: 
male — much enlarged (original). 
