241 
laterally, the apical margin being cleft for some distance; on 
each side of the penis there is often a depression into which 
the process of the periandrium fits when at rest. Within the 
penis at its base there is a process on which the gonopore 
appears to be situated (figs. 14, 32). In the Flatoidinae the 
periandrium is large, forming a short, thick funnel, and the proc- 
esses are shorter; the penis is also shorter and wider (fig. 36). 
The ovipositor is always incomplete. 
PHYLOGENY, 
The classification of animals started early in the history of 
mankind, most likely with the dawn of speech. It was started 
for convenience and was empirical, and has continued down the 
ages on the same lines. With the dawn of biological science it 
was continued scientifically, and a natural order of arrange- 
ment became evident. Since Darwin made evolution a living 
force with biologists the natural arrangement, or natural order, 
has become predominant, in some cases even to the detriment 
of utility. 
The living species of animals represent the terminal twigs of 
the tree of insect life of which we examine but the surface. 

PLATE VI. 
25. Myndus musivus (Cixiidae). Left side view of male genitalia. 
26. gen. sp. ? (Achilidae). Right side view of male genitalia; a, dorsal 
view of aedeagus. 
27. Tambinia formosa (Tropiduchidae). Right side view of male geni- 
talia; a, ventral view of same. 
28. Phaciocephalus sp. (Derbidae). Right side view of male genitalia. 
29. Dictyophara euwropeae (Dietyopharidae). Left side view of male geni- 
talia; a, dorsal view of penis. 
30. Acanalonia sp. (Acanaloniidae). Left side view of male genitalia. 
31. Amphiscepa bivittata (Acanaloniidae). Right side view of male geni- 
talia. 
32. Siphanta acuta (Flatidae). Right side view of male genitalia. 
33. Hemisphaerius moluccanus (Issidae). Left side view male genitalia; 
a, left side view of penis. 
34. Aphelonema vespertina (Issidae). Right side view of aedeagus. 
35. Gelastissus histrionicus (Issidae). Right side view of male genitalia; 
a, ventral view of aedeagus. 
36. Uxantes sp. (Flatidae). Right side view of aedeagus. 
