Collaterial glands (A only) are exclusively present in female cockroaches; they secrete the tanning proteins and phenolic compounds that harden into the ootheca. Male cockroaches possess the mushroom-shaped gland (consisting of utriculi majores and utriculi minores, hence called utricular gland) and the phallic gland (also known as the conglobate gland).

In gradual metamorphosis (Paurometabolous development, seen in Orthoptera, Blattodea, and Hemiptera), the terrestrial immature that hatches from the egg closely resembles the miniature adult (except lacking wings and external genitalia) and shares the same habitat; it is termed a 'nymph'. In hemimetabolous insects with aquatic immatures (Odonata, Ephemeroptera), the young is called a 'naiad'.

During insect spermiogenesis, mitochondria in early spermatids aggregate, coalesce, and form an intricate, giant spherical mitochondrial complex known as the 'Nebenkern'. It is enclosed by an outer limiting membrane and contains a central mass of interwrapped mitochondrial derivatives that subsequently unfold and elongate alongside the developing axoneme of the sperm flagellum.

Specialized reproductive modes in Class Insecta:

• Oviparity: Laying of eggs (the standard mode in most insects).
• Larviparity: A distinct form of viviparity where eggs hatch internally within the female reproductive tract (uterus/genital tract) and the female deposits active, free-living larvae (e.g. flesh flies Sarcophaga, tsetse flies Glossina, sheep bot fly Oestrus ovis).
• Pupiparity: The female retains the larva internally until it is fully grown and deposits a ready-to-pupate larva or puparium (e.g. Hippoboscidae).
• Larvicidal: Refers to chemical agents that kill insect larvae.