96 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 
THE EGG. 
The egg is transparent white, ovoid, slightly more than one-half 
a millimeter in its longest diameter, with one side slightly more 
rounded than the other as in the egg of the pear slug. In eggs in 
which incubation has continued for some time the developing larva 
can be easily distinguished. 
The incubation period of 74 eggs was determined (see Table I), 
and it varied from 4 to 6 days, with an average of 4.9 days. 
Tassie I.—Incubation period of the peach and plum slug, Tallulah, La., 1910. 
Date of Number | Tncuba- 
Lot No. oviposi- iente ol of indi- tion 
tion. mung:| viduals. period. 
= | 
Days. 
| RE AE 2 ee ea Cees orn cps eee eiabic acetate Apr. 14} Apr. 18 1 4.0 
1 Rn Re a ee Mane aby EOS aN MO RR OS Sd, ‘Apr t3)| doe 1 5.0 
EI 0 ve Si oe a ies ete as Ae eee eR i EN in SA Re i Aug. 10 | Aug. 14 6 4.0 
PDE eR Sten Sis etera She is a ee alate toate te see eee ele mies iiere emer Ronee eee Aug. 11 | Aug. 16 3 5.0 
ME DSS Sarai amare Sista leasealeei Sefer ale eind oes eros ene SDSS ee a dOSse4=|se2 doseerr 3 5.0 
DS Cae Se oa Sasa wate see ee aac ance aeeeer eas nace ACig N12) | Feedosee ss 1 4.0 
| Aug. 17 2 5.0 
TA SS oe = alee tO ore tes Cee Ne ee eee oT ae rae erie sad Ossene Aug. 16 1 4.0 
Aug. 17 1 5.0 
1D RS SRE eas SEBS o SABES ae Senne oee rN en OSeas SA or eE BSH aG Se Gas Aug. 14 | Aug. 19 22 5.0 
1 2 eee Rie ate aie RS ee ene yn Seo Anas dors fae doves 29 5.0 
d(C Reenter BE Re CeaHenoRecenmS -Bate san anee aoe socoBoSnnebcos ba abe Aug. 21 | Aug. 27 4 6.0 
Totaliandiaverage:cec. so: Sassen ace eee Eee Re eee | eee ae | Boa Sonne 74 4.9 
THE LARVA. 
As is the case with the pear slug, the larva in escaping from the egg 
cuts a crescent-shaped slit in the wall of its cell. When first hatched 
(fig. 24, 6) it is creamy white with the head slightly darker and the 
eyes ont mouth parts brown, and lacks the slimy covering. It has, 
in addition to the 6 true legs, 7 pairs of prolegs. It begins to feed 
almost immediately, becoming quickly coated with the secretion, 
and within half an hour a line of green appears down its whole length, 
due to the food in the alimentary canal. 
The first damage by the larva consists in very small pinholes eaten 
into the leaf from the underside, all of the tissue being removed except 
the upper epidermis. As the larva grows and its jaws become 
stronger the size of the eaten patches increases until they become 
large blotches. The upper epidermis is, however, never eaten. 
The larva grows rapidly (see fig. 24, c), molting four times during 
its growth. The first instar is from less than 2 to 4 days in duration, 
averaging about 2 days. The second and third instars are of nearly 
ike duration, and the fourth about 3 days in length, the total feeding 
period bemg about 9 or 10 days in duration in warm weather. Two 
individuals were recorded in which the feeding period lasted for 22 
days, but these were from a lot which was under observation during 
