Final answer:
Robber flies do indeed have proboscises, which they use to inject and then consume prey in a liquified form, reflecting their predatory nature-True.
Step-by-step explanation:
The statement that robber flies have straw mouths (proboscis) is True. Robber flies, like several other insects, have specialized mouthparts that are adapted to their way of feeding. In the case of robber flies, their mouthparts are modified into a proboscis, which serves them well in their predatory lifestyle. While some insects, such as aphids and mosquitoes, use their proboscis to pierce plants or skin and suck out fluids, robber flies use their proboscis to inject prey with saliva that contains neurotoxic and proteolytic enzymes. This effectively liquifies the insides of the prey, allowing the robber fly to suck out the nutrient-rich liquid. This mode of feeding is similar to how some other insects, such as butterflies and moths, use their proboscis to sip nectar from flowers.