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. 
Tasre I.—Incubation period of. the peach and plum slug, Tallulah, La., 1910. 
Date of | Number | Incuba- 
Lot No. eyipesl: leer | of indi- tion 
tion | 8: fe period. 
| Days. 
TAR ee eee ee ee i SN tts EE ee Apr. 14/ Apr. 18 | 1 4.0. 
| fy (Ree eS ee ent e Sae SOR RA ea oer aso ossaccoocsceeressocecs Apry 13) 2. .d0S-e—2 1 5.0 
TIT eS ee see eaapene nae HUonaadae oo onesoseouosIsececdeseacosecs Aug. 10} Aug. 14 6 4.0 
De ee ee Nene ae acten psec cena scan scoot se cerereaemeas Aug. 11 | Aug. 16 3 5.0 
oe ee SEPP ARCRn aE Senaeeabone Seb ocootaaneaisnoscescs Sano OE eeleeolnerae 3 5.0 
TRS) ee eee ree a nee SEE REE E Oasis set eee ees Aug. 12)|=..dol-.-- 1 4.0 
Aug. 17 2 5.0 
PANS GS ha Ses eo ina ae Ralaianee a os oe oA eet ers [eccOOsces= Aug. 16 1 4.0 
Aug. 17 1 5.0 
{Oe ee SA ata ere aon bac mae haetae aaeeotooasE SSroeC SSAC Aug. 14 | Aug. 19 22 5.0 
1G gee, So eee a ee RON Sonar E Nate ets S Secs -aeeooteteasce Sodding: Read Ouse- 29 5.0 
LY Beeeeetcoeunaobaar stan anna sbeuceaseuHe seems baesteobbactncr Aug. 21 | Aug. 27 4 6.0 
) 
otalvandiaweragens sees ewe ee see eee a eee ata ee eer eae ee ee eter eee | 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, b) it is creamy white with the head shghtly darker and the 
eyes and 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 
like duration, and the fourth about 3 days in length, the total feeding 
period being 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 
