During walking, insects typically move the mesothoracic legs simultaneously and the prothoracic and metathorcic legs as alternating triangles. The fossil record for insects dates back at least 400 million years to the Devonian period. Special groups of cells set aside in the embryo that do not differentiate until the pupal stage are referred to as imaginal discs. Also explain the function of aeropyles and vitellophages, and what is different about the early cleavages leading to blastoderm formation. Diagram the insect digestive system starting with the mouth and ending at the anus.
Most insects are oviparous, but some are ovoviparous and give birth to live young.
A protective egg case is referred to as an ootheca. Malpighian tubules function somewhat like the human kidney and cleanse the blood of metabolic wastes. Air for respiration enters through the spiracles, travels through the tracheae and into the tracheoles from which oxygen diffuses into the cells. Briefly differentiate between the life cycle of a holometabolous and a hypermetabolous insect. Briefly answer each of the following questions in a sentence of two.