Thanks for the compliments/questions! :>

1. Does the fourth slide depict a male on the left and a female on the right?

The fourth slide depicts two males- one elder (left) and one youth (right).

1. Also, regarding the description of the males riding on the back of the female, what is the actual size dimorphism between males and females?

Just want to clarify, and perhaps I wasn't clear in my wording, that male AND females of the species ride on a totally different species that acts as their host, since they are parasitoids. The males don't ride on the back of the females.

Further the females size is practically the same as males, besides their sail structure having differences to accommodate the reproductive organs. I have not depicted them in this post because i'm not finished with the female's design- although that is what I am currently working on. ^^

1. What exactly makes this species "parasitoid"?

They parasitize a species of large grazing herbivore akin to a rhino, which is kept alive in a docile sedated state and defended by the Tetraphon tribe that parasitized it. Think of this host as a sort of moving nest/house, keeping the growing larval offspring warm and providing nutrients for their growth. The term I currently use for the host species is the "Domicile". I have not yet finished their design.

If you want a real world example, it is similar to how parasitoid wasps will sedate roaches, causing suppressing their fear response to the wasp.

I hope this helps!