6 BULLETIN 1243, U. S. DEPARTMENT OF AGRICULTURE. 
LIFE HISTORY AND HABITS. 
The adult (Pl. IV, A) begins to feed immediately on arrival in the 
bean field from winter quarters. Females may begin to lay eggs 8 
days after emergence from hibernation and possibly sooner, but the 
majority feed for a longer period, the average time being 14 days for 
6 females in 1922. The adult feeds on the under surface, usually 
puncturing the leaf and leaving ragged holes, some very small, 
others one-fourth inch across. Only a very small percentage of 
feeding takes place on the upper surface. 
Mating occurs in most cases in the fall, but also in the spring. 
The abdomen of the gravid female gradually becomes dadention and 
is noticeably enlarged 24 hours before oviposition. Females are 
then easily distinguished from males. An individual female has 
deposited as many as 1,669 eggs during a season. [Eggs are usually 
laid in groups of from 40 to 60, averaging 51 for females observed by 
the writers in 1921 and 1922. Eggs (Pl. IV, B) are almost invariably 
placed on the under surface of the leaves in rather compact groups. 
In midseason a female will deposit a group of eggs quite regularly 
every two or three days until death. 
The egg-laying records of a few representative females chosen from 
69 complete experiments in 1921 and 1922 are given in Table 1. 
Included also is the time between emergence and the first egg laying. 
The beetles of the fourth generation did not lay eggs. The records 
of mating are the observations made while attending to the experi- 
ments and are not complete. Hach experiment included a male and 
female, except in the cases noted. 
TABLE 1.—Egg deposition records of a few representative females of the Mexican 
bean beetle in cages, Birmingham, Ala., 1921 and 1922. 
1921. 
OVERWINTERED FEMALES. 
No. LH-3: Female collected in field March 26; more than 10 days between emergence and first eggs. 
Eggs. Eggs. Eggs. 
ADT os eee eee area GSU Soave o, see eee eee 60.) May. 28. 5c. Pou es 
eee’ Set eke ee 72 Ways he Ge ee 55 Oe et cas pee ae 53 
1 Oe Reema abc es 74 Wis 52535 Socbacsddseose 60 || Jume 3.2 2.055. eee 52 
Die ees eee 48 PA ere aire eines See 53 Cc eeeb one aases eee 31 
ee ee PE es 68 18 ae ea eS A 2 hy 64 
| oe es a 72 2 RR SS 8 ee (oe. 54 Dotel sf ate see 1,005 
May (Open sees eee eee 63 
No. LH4-2: Female 1 dormant from hibernation cage March 24; 42 days between removal and first eggs. 
Eggs. Eggs. Eggs. 
Mae 5s a eee eee OS (aL ys 7: Be ee Seem 57 Jam: Oo. one moene nee 54 
TSe2. 0 ee ee eee 56 OPES Sate Senn eee ees 58 Oe C vanne tecke eee 57 
182 dk cel Seep eee eee 57 2! OE ET SO ae 3 ia ep 58 
iN aint cee eee DG; OHS ates etcetera ce Reeee 58 LUGHL. .catsueeereens 572 
FIRST GENERATION FEMALES. 
No. LH-4G: Female emerged May 20; 11 days between emergence and first eggs. 
Eggs. Eggs. Eggs. 
Magee Lory sabe 2 oe bee cone ial DUNDL sso acne ek Ge aaa ee 64 i) July. 6.4... S2ch pecan kes 55 
Ufbie(: oe: See eee oe 41 7) EE Pe ts, tape 57 Oia dawns poke 51 
fA oe meg hag fo 53 72 ie esa 8 Gree 2 FS 53 AL titi ccceutas Coes 54 
OE ee a ee aed aoe 52 DR 8a ees a eee 56 1B awins cue teed ate eee 
LG rg SRB a ble at it depen’ 59 £31 fab ope pig) cy g Sci 53 — 
Use See pes Gee ge Ba) Jal hes Sk eee eee 54 LOtALS Si ceccdemceeene 1,013 
yy pe sere ee ere = BBS had oe cee ene oe eee eee 
LOS op kac eee ee 55 Te ae rae see oe 55 
1 This female had no opportunity to matein 1921. All groups defosited were normally fertile. 
2 Mating observed this date. Females paired when emerged except in case of LH-9 and LH4-2, 1921, — 
which were isolated. 
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