Half of spermatozoa are without allosomes in

An allosome is a hetero-chromosome that differs from normal alleles in aspects like size, form, and shape. X and Y chromosomes are allosomes. The sex determination in insects of Hemiptera and Orthoptera is based on the presence or absence of X and Y chromosomes. Those zygotes with two X chromosomes develop into females and those with both X and Y chromosomes or just one X chromosome develop into males. Usually, half the gametes in insects of Hemiptera and Orthoptera lack an allosome and on fertilization with an ovum containing only chromosome result in males.