858 
Journal of Agricultural Research 
Vol. XXX, No. 9 
In Table III the conspicuous features 
are the large numbers of eggs laid by 
several of the females, the length of the 
records, the marked differences in fe¬ 
cundity of the females, and the long 
rest periods during which no eggs were 
laid. As the present report appears to 
be the first detailed account of the 
biology of a representative of the large 
family Cleridae, there is no opportu¬ 
nity for comparison of the life history 
of Necrobia rufipes with an allied form. 
As shown by Table III, mated fe¬ 
males continued to lay eggs for several 
months after having been deprived of 
the male through its death or escape. 
The male of pair No. 14 escaped 
December 5; eggs laid by the female 
January 18 and March 5 produced 
larvae. As previously noted, eggs laid 
by old females not infrequently col¬ 
lapse and fail to hatch. This occurred, 
for example, with the eggs of pair No. 
2, which were laid April 23 and May 3, 
and the eggs of pair No. 9, laid on May 
2. The records detailed in Table III 
are summarized in Table IV. 
Table IV .—Oviposition and longevity 
of Necrobia rufipes, 1922 and 1923 ° 
[Food: Larvae of Piophila casei] 
Pair No. 
Male and female emerged and 
mated 
Longevity of male 
Longevity of female 
Duration of period, mating to 
oviposition 
Duration of period of ovi¬ 
position 
Duration of period, end of 
oviposition to death of female 
Total number of eggs laid 
1922 
Days 
Days 
Days 
I 
Days 
1 
Days 
1 
Sept. 1 
242 
i b ) 
7 
\ 236 
\ ( b ) 
846 
2 
Sept. 6 
375 
258 
2 
1 237 
19 
1,316 
3 
___do_ 
229 
226 
3 
! 124 
99 
1,087 
4 
__-do.— 
201 
267 
2 
1 119 
146 
301 
5 
Sept. 11 
296 ! 
378 
155 
205 
18 
1,197 
6 
Sept. 12 
242 
237 
5 
159 
73 
1,088 
7 
Sept. 16 
222 
289 
i 4 
221 
64 
481 
8 
___do_ 
289 
409 
8 
369 
32 
1,497 
9 
-__do_ 
238 
277 
, 58 
196 
23 
583 
10 
_--do._ 
430 
277 
28 
237 
12 
1, 029 
11 
Sept 18 
234 
121 
4 
99 
18 
576 
12 
---do_ 
161 
256 
20 
211 
25 
! 854 
13 
Sept. 19 
235 
304 
6 
215 
83 
! 744 
14 
L--do_ 
( h ) 
260 
17 
153 
90 
I 598 
i Sp.nt. 90 
229 
30 
1,042 
16 I Sept! 21 
354 
368 
12 
323 
33 
2,131 
17 
Oct. 6 
131 
283 
22 
43 
218 
i 351 
18 
I Oct. 16 
325 
194 
2 
132 
60 
876 
19 
Oct. 20 
157 
389 
; 8 
147 
234 
706 
20 
Oct. 21 
248 
1 
246 
113 
1 127 
6 
! 823 
1 
“ This table is a summary of the records detailed 
in Table III. Compare with Table II. 
b Escaped. 
DEVELOPMENTAL PERIOD 
In the first rearing trials larvae 
were provided with what appeared to 
be the preferred food—stale bacon. 
This was heated to about 120° F. for 
a day or two in order to extract some 
of the low-melting-point fat, which 
was so abundant in unheated pieces 
of bacon that the larvae were often 
smothered in it. Although larvae 
usually become large and vigorous 
when they develop in whole hams, 
shoulders, or sides of bacon, the mor¬ 
tality in vials containing small pieces 
of the same meat was high and de¬ 
velopment slow, frequently resulting 
in dwarfed individuals. The results 
of the rearing experiments in which 
stale fat bacon was used are assembled 
in Table V. 
Trials shown in Table V were prelim¬ 
inary, but the results, compared with 
those given in Tables VI and VII, show 
that an exclusive diet of smoked pork is 
not the most favorable food for larvae 
reared in close confinement. 
In some of the rearing work done 
subsequently to that shown in Table 
V the ham-beetle larvae were fed only 
skipper maggots. Newly hatched 
larvae were transferred to Petri dishes, 
10 or 20 to a dish, where they were 
given crushed skippers until nearly 
full grown, when live skippers were 
provided. The mortality in these 
dishes was nearly always high. There 
was probably cannibalism, and the 
soft posterior proleg of the very young 
larvae often stuck to the smooth glass, 
resulting in their death by starvation. 
Records of the development of larvae 
fed with skippers are given in Table 
VI. A comparison of this table with 
Table V shows the advantage to the 
insects, when closely confined as larvae, 
of a diet of maggots in the place of 
stale bacon. 
In Table VI the shortest develop¬ 
mental period is shown to have been 
30 days, including 17 days as a growing 
larva and 13 days within the cocoon 
as larva, prepupa, pupa, and adult. 
According to the results included in 
Table I the incubation period may be 
as short as 4 days; the minimum pre- 
oviposition period recorded (Table IV) 
is 2 days. The life cycle, therefore, is 
possibly as short as 36 days. 
The details of the larval life are given 
in Table VII. In this set of experi¬ 
ments individual larvae were reared in 
large veterinary capsules, as explained 
previously under “Larval behavior.” 
The larval stage is divided into three, 
sometimes four, instars. 
