4 BULLETIN 235, U. S. DEPARTMENT OF AGRICULTURE, 
mined at the Sacramento laboratory during June, July, and August, 
1913, as follows: Egg stage, 6 days; larval stage, 35 days; pupal 
stage, 12 days; adult, about 14 days. Total, from egg to adult, 53 
days, or 1 month and 23 days. - 
While the subject of this article is practical and-based on condi- 
tions at Sacramento, Cal., it should be added that in the case of the 
life history of this species Dr. Chittenden has pointed out ! that ‘‘ex- 
periment shows that the insect is capable of passing through all its - 
several stages from egg to adult in five weeks, which furnishes a pos- 
sibility of six or more generations in a well-heated atmosphere, 
although in a moderately cool granary or other storehouse four or five 
broods is probably the normal number per annum.” 
The sudden appearance of large numbers of larve in dried fruit 
is readily explained by Table I, which shows the number of eggs 
deposited by six moths which were Commied in the laboratory to 
determine the rate of oviposition. 
TaBLE I.—Egg-laying records of the Indian-meal moth. 
Days 
No | Total 
ist 2d 3d 4th 5th. 6th 7th 8th 
tae ee 46 79 36 23 24 16 1 pee (eae sees 235 
Dre: 56 65 Bih 36 36 21 Gig caries 0 
Sets 39 43 34 18 16 Oi oe | ree 156 
Ares 16 33 47 64 45 56 12 13 286 
Sieeee 59 51 55 38 26 Eien PRS ee 4 bees 234 
Se a eae san Ee aie aT Bc ea |S ck wale mn ne | ae | Dc 168 
1 The number of eggs in this vial was determined as total and not by days. 
Average number of eggs deposited by the six moths, 221.3. 
These eggs were deposited mostly during the night. 
The life cycle during the summer, as given in a preceding para- 
graph, is only 53 days. Starting with one fertile female in a packing 
house on June 15 (provided all of the insects matured), there would 
be 221 moths by the following August 15, and by August 30 (pro- 
vided that half of these moths were females) there would be a total of 
23,310 larve in the dried fruit. 
Under natural conditions some of the eggs do not hatch and many 
of the larve fail to mature, but from the foregoing data it is readily 
understood that a few moths of this species are capable of producing 
a very severe infestation within a relatively short time, provided that 
temperature and other conditions are favorable.? 
1 Chittenden, F. H. Some Insects Injurious to Stored Grain. U.S. Dept. Agr., Farmers’ Bul. 45, 24 
p., 18 fig., 1897. See p. 10. 
2 The hymenopterous parasite Habrobracon hebetor Say is frequently found attacking the larve of the 
Indian-meal moth, but it has not been observed appreciably to affect the infestation in California. 
