70 Trans. Acad. Sci. of St. Louts 
No. in each Number of No. in each Number of 
egg case egg cases egg case egg cases 
12 2 16 15 
13 5 1% 3 
14 6 18 oe 
19 10 Total____43 
It is at once apparent that the mean number at which 
nature aims is 16, and her deviations from that are not 
significant; even the mortality in embryo is surprisingly 
small. 
Food of nymphs and adults—During the period of 
observation an attempt was made to keep a record of 
food materials which they accepted. Soon, however, the 
list became so voluminous that it was apparent that it 
would be more brief and simple to list the things which 
they did not eat. This dwindled almost to nothing. They 
showed a preference for the softer portions of the food 
before them, and left the hard or chitinized portions, but 
otherwise they ate everything of a vegetable or animal 
nature, either fresh or decaying, which came in their 
way. 
Cockroaches are undoubtedly attracted to their food 
by the sense of smell located in the antennae. Lloyd 
Morgan * tells us that if their antennae be extirpated or 
coated with paraffin, the roach no longer rushes to food, 
and takes little notice of and will sometimes even walk 
over blotting-paper moistened with turpentine or benzo- 
line, which a normal insect cannot approach without 
agitation. 
Enemies.—Dermestes larvae often infest the egg cases 
of the roach. Some large frogs of the edible variety 
SAnimal Life and Intelligence, p. 257. 1891. 
