“Look out everybody, things are about to get awesome!”
Larval Varkids attack by quickly skittering up to their enemies and scratching/biting them or by leaping or flying at them. Unless they are in a very large group, they are little more than a nuisance and can be easily dispatched with one or two melee attacks.
Blood Varkid is not another stage of varkid evolution, but rather a stronger variation of the Larval Varkid that randomly appear in the True Vault Hunter Mode alongside the normal varkid groups. They are completely identical aside from their increased health, damage, and red coloring. The Blood Varkid will morph to the Adult Varkid, just as the Larval.