LIFE HISTORY AND HABITS: THE LARVA. 55 
Taste XIX.—Course in fruit taken by newly-hatched plum-curculio larve—Contd. 
Dates of Bs Fruits 
observa- Kind of fruit. Leeann of exam- Course taken by larve in fruit. 
tion. PuEGhes: ~ | ined: 
May 16...-.- Red June plum....... BaS@ucineinco a 1 | In to base of pit. 
Veen Early Belle peach..... Center side.... 1 | In to pit. 
One Wild plumc..<.4....4 Basal! $c. sceee 1 | Under skin about + inch, and around to 
center of side, then into pit. 
Apical 4......- 1 | Into pit. 
Basalisos so -5. 1 | Straight in and into pit. 
Apicalide eo 1 | Straight into pit. 
ee oneeccelesincnleee es Ogee eee 1 | In straight to apex of pit, and then around 
to center of other side of fruit. 
eeeUOecccseseecscscas: Apical's. <<... =. 1 we ppical 4 of pit, then along pit to center 
of side. 
Seen Pte AO sansa cu cieccaseias IBaSOee es ceceet 1 | Intopit; around to center side and into pit. 
Gs GOees a eect bese Center side... . 1 | Into about center of fruit, then to basal 4, 
and down toward pit. 
Sseec| Kees Owiscs-osseeess5-]=i55- GOe- nstece 1 | Straight into pit, then along pit to apical 4; 
then down side of pit. 
Prof. Crandall has recorded observations on the course taken by 
larve hatching in apples, as follows: 
The course taken by the larve on emerging from the egg has been traced in a number 
of apples, and is found to be variable. In one apple examined the bore proceeded 
straight from an egg cavity near the basin to a point just beneath the skin on the 
border of the cavity. Another bore was traced in a spiral 24 times around the fruit. 
Other bores were found to be tortuous, but in no apple examined did the early bore 
extend to the core. 
LARVAL INSTARS. 
The number of molts made by the curculio larva in the course of 
its growth has not heretofore been determined, probably on account 
of the difficulty of following the growth of the insect in the fruit. 
Mr. Hammar, during 1910, in Michigan, determined the number of 
molts and length of the respective instars for 10 individuals, as 
shown in the following table: 
TaRLeE XX.—Larval instars of the plum curculio. 
Dates of molting. 
Individual No. 7 2 : ee S 
irst econ ir t 
Hatched. molt. molt. molt. fruit. Adult. 
June 28} June 30] July 2)| July 5j| July 9/| Aug. 4 
June 30} July 2)| July 4] July 6 dose Aug. 10 
=e Eee 002-82 | ido ee Edo aly 7) |e aoe = || Aug. 14 
Jaly “| ulys 3h Tulys 7) | duly LO oly? 1b |S2ce2so-- 
ot See do... -do.....| July 6{|July 9{| July 14] Aug. 16 
July 2°) July 4 '|<..do...-- July 8] July 11] Aug. 12 
-.-| ae do.....|.-.d0,--..) July 7} July 9°| July 12 | Aug.15 
July 4] July 6] July 8] July 11] July 16] Aug. 29 
July 5] July 7] July 9/] July 12) July 18] Aug. 15 
