The groups into which the Coccididæ are, in this work, divided are as follow:—

1. Female insects constructing for themselves shields composed partly of secretion, partly of the pellicles discarded from earlier stages; abdomen not cleft; legs lost at full growth.

[Diaspidinæ.]

2. Female insects naked, or covered with shields of secretion, either waxy, horny, cottony, or felted; abdomen in all stages cleft; legs either lost or retained at full growth.

[Lecanidinæ.]

3. Female insects naked, or covered with shields of waxy secretion; abdomen of larva ending in prominent processes, abdomen of adult cleft; legs either lost or retained at full growth.

[Hemicoccidinæ.]

4. Female insects naked, or covered with secretion either waxy, cottony, or felted; abdomen in all stages ending in prominent processes; legs either lost or retained at full growth.

[Coccidinæ.]

Life-history.