THE HORSE-RADISH FLEA-BEETLE. 9 
TABLE 1.—Egg record of a single female horse-radish flea-beetle. 
Number 
Date. of eggs Remarks. 
deposited. 
May 17 DONG RRR aS IN ara Syne Rr RO ER SEE a 
27 POOR INNS es x NEA ea oe ely 3s RE Rees aot ARE pe Rr 
28 IL aR Sec a avs oss Re RR EE a a Ge AOS 
June 3 23 Within 48 hours 
a PAO EN Ne at RM ge Ue So ee a 
8 PP | eee se eee I Uta Spe A Dee na 
14 CMe | ee ea EINER sR eR SL pag Bey SN Le a tk, 
ICOM see etree ie Male added. 
21 DM | eae tN pa are sere eyo awe PB oe ae 2) 
DON Fay Aish aoe ys Copulating. 
25 44 | Within 48 hours. 
27 Ag | iy eras Senet ra Nee rae err aRt nS Reaves 2 Gly) 
29 44 Within 48 hours. 
BORG ests ora ae Copulating. 
July 1 28 | Hatched July 12. 
2 OLR | Sh rear pa a ae aim tans a eens ayia Sat eye tage Re SY 
3 PPX S| ia Te AS Bi DA ie ac Te a ea SSA ee Ee eee ae 
12 39 | Within 72 hours. 
I |e ste geese ae Mass; not counted; estimated at 22. 
WA i aarcinteieteereee Copulating; eggs laid about July 11 
hatched. 
U1 Sie pene ere Copulating. 
22 7 | Copulating; within 36 hours. 
30 26 | Within 5 days. 
Aug. 3 22 | Within 72 hours. 
(ial (eect rere Female dead; male still alive. 
1 Within 24 hours in each case, unless otherwise mentioned, eggs were always removed. 
Incubation.—The incubation period of the egg varied from 7 to 14 
days, as the following data show: 
TABLE 2.—I/ncubation period of eggs of horse-radish flea-beetle. 
Area When deposited. | Date of hatching. Incubation period. a 
Days. 
20) ee eeiaansis Ma yale, Secon cc Before May 17....| 14(approximate)...-. May 17. 
(C5) SSR ESE 3S Sa aeeers GOrs dees ee Ikan Talos a 10) pe ae et ee an ee haat ee 
SORES ase Many lai say res Maiya2one aasaersaer EUR ea aL CE aS al RECOIL Sa 
DSK NeR eo ete Sunliyztep es Ser Duly alse epee ae TU Leta a CaS ec a ag eee tafe | 
J lyelO SNe aul yale es hi (ADPLOXIMALS) sssees|ee = soe =~ 
See sae IMINO Ze ees Diuby24 OT Ose ee SiG pPpProximate)es aval. ssn. | 
. The months of May, June, July, and August were from 3.6° to 
5° FEF. below normal. 
THE LARVA. 
On hatching the young larva crawls about the leaf for some time. 
Several individuals, observed over an hour, showed no particular 
course. Some went up toward the tip, others toward the crown, 
where they were lost from sight, but none started feeding. A smail, 
tender petiole, recently invested by numerous larve, showed that 
they had entered at different places along the inner side. 
As the larve grow and feed in the tissues of the petioles and mid- 
ribs of the leaves, their presence is indicated by darkened or dead 
areas, where they have approached the surface. When the larve are 
