THE HOP FLEA-BEETLE. 81 
year would undoubtedly be a more opportune time for getting the younger 
stages, but our rearing-cage experiments, starting with the beetles in mating, 
should give us ample material for the study of the younger stages. The scarcity 
of the larvae at the time when sought is attributed by the writer to the fact 
that it was too late for the large numbers of spring and too early for those 
expected to appear about six weeks later, according to reports of previous years. 
Those few which were obtained are probably late individuals of the last brood. 
Two other kinds of larva? are taken commonly in the ground, these being wire- 
worms and carabid larva?. Many of these are very small, just about the size of 
our flea-beetle larva?, and the wireworms, when first hatched, are of the same 
white color, but both of these forms of larva? can be readily distinguished from 
the flea-beetle larva?. The few pupa? obtained are undoubtedly those of what 
we consider the flea-beetle. 
Development. — From all accounts this flea-beetle keeps emerging continuously 
throughout the season, though there are periods when the beetles occur much 
more abundantly than at others. Last year Mr. Hulbert stopped using the 
tarred boards June 1, when practically all of the beetles had disappeared. They 
did not reappear until the last week in July, when the jarring method was 
resumed. This year (1908) he continued the use of the tarred boards up to 
the second week of July, this difference over 1907 being attributed to the cold 
wet season. According to this, the next lot of beetles may not appear before 
the last of August of the present year. Beetles have been seen breeding con- 
tinuously during the past two weeks, though not abundantly, one pair being 
seen out of seventy-five or one hundred beetles. Beetles are usually present in 
considerable numbers in the fall, when the hops are mature, and do much direct 
injury to the product. 
NOTES ON OTHER SPECIES. 
A few remarks in regard to the larval habits of our other American 
and some European species of Psylliodes may be interesting. The 
writer has several times observed the beetles of the equally well- 
known PsylJiodes convexior Lee. in numbers on shepherd's purse 
{Bursa bursa-pastoris) in June near the District of Columbia, and 
it is probable that this is the larval food plant. Until the publica- 
tion of Mr. Quayle's article 12 there was no record of any of our four 
species having been reared; hence, the natural conclusion that they 
were root-feeders. In Europe no less than forty-nine species of 
Psylliodes are recognized in a recently published catalogue 1 and the 
habits of those which have been studied indicate a preference for 
cruciferous plants, although several are attached to widely differ- 
ent groups of plants. Thus among European species are the hop 
flea-beetle (Ps. attenuate Koch), the potato flea-beetle [Ps, a/finis 
Payk.), and a species which is mentioned and figured by Taschen- 
berg & as the " raps-erdfloh " (Ps. chrysocephala L.). The last is 
very abundant and has been known for years to attack edible crucif- 
erous crops. It has been recently treated (1906) by Mr. Geo. 
a Reitter, Catalogue Coleopterorum Europce, pp. r>7L > -oT4. 1906. 
b Praktische Insekten-Kunde, l't. 11. p. 903, flg. 1\). Bremen, 18T9l 
