In grasshopper males have one X only (XO type), in Drosophila males have one X and one Y (XY type)- Males in both produce 2 different kinds of gametes so heterogametic.
Detailed answer:
In grasshoppers there is found XX-XO type of sex determination. Males have only one sex chromosome and therefore produce two types of male gametes : one with X chromosome (A + X) and the other without sex chromosome (A + O), thus shows heterogamety.
In Drosophila there are two sex chromosomes (XY) which are heteromorphic and therefore two types of male gametes : one with X chromosome (A + X) and another with Y chromosome (A + Y).
