1914] | Natural Control of Toxoptera. 81 
upon the Aphids. The larval stage lasts from about ten to 
thirteen days during which time they eat, on an average, 320 
Toxoptera per larva,—that being about 26 to 28 Toxoptera 
per day. The pupal stage lasts six to 10 days and about 30 
to 35 days elapses from the time that they emerge until they 
lay eggs. During this time, they eat about 825 Toxoptera per 
ladybird, making an average of about twenty-five per day to 
each ladybird. 
In this species, all the eggs seemed to be laid during one 
period which lasted for about a week to ten days, during which 
time they laid about 100 to 150 eggs. After having completed 
the egg-laying, they live for some time before they die. The 
Adalia seems to live about three to four months,—the males 
dying first. In one experiment, the larvae were hatched from 
eggs laid on the 10th of October, 1912, the last ladybird died 
on the 24th of February, 1913,.and the average number of 
Toxoptera destroyed was 2844 per ladybird. In this experi- 
ment, the ladybirds were given as many Aphids as they could 
eat. When the Aphids were scarce, the ladybirds would not 
pass as rapidly through the different stages and the number of 
eggs laid by the adults had a direct bearing upon the quantity 
of food present. When the food supply runs short, the eggs 
which have already been laid will be eaten while even the larva 
will eat each other and the adults will eat the larve. 
In the case of the Red Spotted Ladybird, we have a larger 
species, being about 3-10 inches in length and nearly as wide,— 
hemispherical in shape. The adult ladybird of this species 
will lay from 150 to 250 eggs during her life. The egg-laying 
period seems to be divided into several different stages. In 
feeding experiments with the larve of this ladybird, it was 
found that during the ten days of its larval existence, each 
larva eats about 440 Aphids. Another interesting point is that 
the normal life of the Red Spotted Ladybird is much longer 
than that of the Black Spotted,—being about four to six months. 
Both of these ladybirds were found to be parasitized by a 
species of Dinocampus. The parasite laid its eggs in the larva 
and in some cases, probably, in the pupa. The cocoon of the 
parasite is formed underneath the adult ladybird and it seems 
that the ladybird always reaches the adult stage before the 
larva of the parasite emerges from the ladybird’s body to form 
