THE HOP FLEA-BEETLE. 81 



year would undoubteclly be a more opportune time for Retting the younger 

 stages, but our rearing-cage experiments, starting with tlio beetles in mating, 

 should give us ample material for the study of the younger stages. The scarcity 

 of the larvai at the time \A'heu 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 rei)orts of previous years. 

 Those few which were ol)tained are probably late individuals of the last brood. 



Two other kinds of larv:e are taken commonly in the ground, these being wire- 

 worms and carabid larvie. ilauy of these are very small, just about the size of 

 our flea-beetle larvre, and the wireworms, when first hatched, are of the same 

 white color, but both of these forms of larvae can be readily distinguished from 

 the flea-beetle larvje. The few pupae obtained are undoubtedly those of what 

 we consider the fiea-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. Ilulbert stopped using the 

 tarred boards June 1, when practically all of the beetles had disappeared. They 

 did not reapi»ear until the last week in July, when the jarring method was 

 resumed. This year (190S) 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-flve 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 Ps3'lliodes may bo interesting. The 

 writer has several times observed the beetles of the eqiuilh' well- 

 known Psylliodes convexior Lee. in numbers on shepherd's purse 

 {Bursa hnrxd-j^astor'is) in June near the District of Columbia, and 

 it is probable that this is the larval food plant. Until the publica- 

 tion of Mr. Quajde's article ^- there was no record of any of our four 

 species ha%ang been reared; hence, the natural conclusion that the}^ 

 were root-feeders. In Europe no less than forty-nine species of 

 Psylliodes are recognized in a recently published catalogue,*" 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. attenuata Koch), the potato flea-beetle {Ps. (ifjinis 

 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 cro2)s. It has been recently treated (li)0()) by ^Ir. Geo. 



" Reitter, Catalogus Coleopterorum Europae, pi). 572-574. 1900. 

 * Praktische lusekten-Kundc, Pt. II, p. 303, flg. 79. Bremen, 1S79. 

 66— VI 



