1 1 8 
Psyche 
[March 
Table I. Continued. 
Mean percent 
dry material 
in leaves 
Plant species ± SE 1 * 2 
Taenidia interqerrima 
24.31 
+ 
0.64 
3.97 
± 
0.13 
2.81 
+ 
0.20 
Yel low pimpernel 
N 
= 
30 
Thaspium barb inode 
30.79 
+ 
0.58 
3.93 
+ 
0.23 
2.22 
+ 
0.19 
Meadow parsnip 
N 
= 
28 
ZIzia aptera 
19.80 
0.73 
4.31 
± 
0.17 
3.21 
+ 
0.22 
Heart shaped alexanders 
N 
= 
27 
Zizia aurea 
23.53 
+ 
0.16 
4.25 
± 
0.19 
4.23 
+ 
0.1 1 
Golden alexanders 
N 
18 
®The significance values 
of the »1 
-r 
statisti 
ic with 
30 df are: 
0.05 
= 
2.042, 
0.01 = 2.750. 
2 T = 5.666 
3 T = 0.422 
4 T = 2.349 
The larvae reared on the 32 umbellifer species all ingested ap- 
proximately the same total amount of food, averaging about 144 dry 
weight mg, during the 4th instar (P < .3) (Table 2). Generally, 
all larvae completed the 4th instar in about 3 days (P < .3), thus 
the rate of food consumed also did not vary significantly (T = 0.247, 
P < .4). The proportion of ingested food which was digested and 
assimilated (‘Approximate Digestibility’) averaged approximately 
53% for the larvae reared on the cultivated umbellifer species and 
about 47% for the larvae reared on the wild umbellifer species 
(P <0.05). The efficiency with which ingested food was converted 
to larval biomass ranged from approximately 25% for the larvae 
reared on the cultivated umbellifer species to approximately 19% 
for the larvae reared on the wild umbellifer species ( P < 0.05 ) . 
The efficiency of conversion of digested food into larval biomass 
did not vary significantly between the two groups of plants tested 
and averaged approximately 45% in all cases (P < .2) (Table 3). 
Individual larvae gained on the average approximately 10 dry wt. 
mg more on cultivated umbellifer species than the larvae reared on 
wild umbellifer species, during the 4th instar (P < 0.05). This 
Mean calories 
per mill igram 
dry weight of 
leaf material 
± SE 1 > 3 
Mean percent 
of nitrogen 
in leaf material 
± SE*, 4 
