Ylll 
CONTENTS OF YOL. I. 
CHAPTER IX. 
Secondary Sexual Characters in the Lower Classes op 
the Animal Kingdom. 
These characters absent in the lowest classes — Brilliant colours — 
Mollusca — Annelids — Crustacea, secondary sexual characters 
strongly developed ; dimorphism ; colour ; characters not acquired 
before maturity — Spiders, sexual colours of ; stridulation by the 
males — Myriapoda Page 321-340 
CHAPTER X. 
Secondary Sexual Characters op Insects. 
Diversified structures possessed by the males for seizing the females 
—Differences between the sexes, of which the meaning is not 
understood — Difference in size between the sexes — Thysanura 
— - Diptera — Hemiptera — Homoptera, musical powers possessed 
by the males alone — Orthoptera, musical instruments of the 
males, much diversified in structure ; pugnacity ; colours — 
Neuroptera, sexual differences in colour — Hymenoptera, pug- 
nacity and colours — Coleoptera, colours ; furnished with great 
horns, apparently as an ornament ; battles ; stridulatin£ organs 
generally common to both sexes 341-385 
CHAPTER XL 
Insects, continued . — Order Lepidoptera. 
Courtship of butterflies — Battles — Ticking noise — Colours com- 
mon to both sexes, or more brilliant in the males — Examples — 
Not due to the direct action of the conditions of life — Colours 
adapted for protection — Colours of moths — Display — Per- 
ceptive powers of the Lepidoptera * — Variability — Causes of the 
difference in colour between the males and females — Mimickry, 
female butterflies more brilliantly coloured than the males — 
Bright colours of caterpillars — Summary and concluding re- 
marks on the secondary sexual characters of insects — Birds 
and insects compared 386-423 
