Also Mothra has always had mouth parts.

Its very unlikely she is a hornet. She was also designed to be a giant-moth like kaiju. Her wings do look similar to some of the bigger species of Moths like the Atlas Moth and Lunar Moth. Her wings aren't translucent. And most of her design is meant to be moth-like, but with Mantis and Wasp-like aspects thrown in there.

This is what Wikizilla has to say about the Design:

https://wikizilla.org/wiki/Mothra_(Monsterverse)

*Godzilla: King of the Monsters director Michael Dougherty regarded Mothra as the most difficult monster to redesign.[7] He directed his team to give her more physicality than previous incarnations, and they came up with a wasp-like stinger and mantis-like spiked forearms. These weapons would look out of place on most Toho Mothras, but the designers opted to make her body more sleek and streamlined, closer in proportions to a real insect. Feeling that early designs were too tank-like, they settled on something closer to a jet fighter.[8] Elements of dragonfly wings, hornets, butterflies, and of course, moths went into her new look.[8] Dougherty also revisited the film Starship Troopers, possibly for the Brain Bug.[7] The spots on her wings were patterned after Godzilla's eyes to allude to their symbiotic relationship.[9]

Mothra (Monsterverse)Wikizilla

Mothra is one of the few explicitly female kaiju, and Dougherty wanted her body to look like an "old vase."[8] According to Legacy FX member Luca Nemolato, "The idea was that this civilization in the past had seen her and been inspired by these shapes to create their fertility gods, and she's the mother queen of them."[8] Cast and crew alike regarded Mothra as a more spiritual, even angelic monster, representing "Mother Nature's protector," and a perpetual cycle of death and rebirth.[10] But she also had to look dangerous, necessitating a delicate balance in her features. Needless to say, it can be difficult for a human audience to glean much emotion from the face of a moth, so the animators developed a highly advanced face rig for her model.[8] Her mandibles, wings, and legs all helped her emote as well.

Mothra's larval form really only appears in a single scene, but her design still required great care, going through "a zillion different versions" in the words of Ortega.[8] The first monster in the film audiences see for an extended period, she needed to go from scaring them to charming them in a matter of seconds. As insect larvae don't have much in the way of faces, the designers had to weld together aspects from several larvae and adult insects to give her eyes and a mouth.[8] Even though she was a newborn, the team wanted her to still feel tough, so they armed her with claws and as armored plates.

Though all four of the movie's main Titans have bioluminescence, Mothra's is the most extreme. As a larva, she emits orange light when alarmed, red when enraged, and blue when calmed, a nod to the larvae in Godzilla: Tokyo SOS changing their eye color when their mother died.[7] Dougherty wanted the imago to leave trails of luminous dust that gave her a comet-like tail as she flew, but in the interest of not having every scene be overpowered by her presence, he opted to have it disperse as she flew and mix in with surrounding clouds.[8]

While Mothra was present in the first drafts of Godzilla x Kong: The New Empire, Legendary's ability to renew their rights to Mothra was tenuous enough that a placeholder monster named Phosphera was used during production. Phosphera was present during some test screenings, and an image of it leaked online; once Mothra's inclusion in the film was confirmed, rumors began to circulate that Phosphera was poorly received by test audiences and so was hastily replaced by Mothra. However, director Adam Wingard later clarified, "The plan was always Mothra. But we weren't sure if we were going to be able to get Mothra. [...] I don't like that some people think it wasn't the plan all along. If you look at the very first draft of the script, it always says Mothra."[11] Despite Wingard's phrasing that Phosphera's use was "brief," all utterances of Mothra's name in the finished film are spoken by characters off-camera, suggesting that the on-set reads of these lines referred to Phosphera instead and were redone during post-production. Dougherty's initial idea of Mothra leaving behind dust as she flies was somewhat incorporated in the film, with her wings scattering golden trails of dust.

Design

The Monsterverse Mothra's design is very different from past incarnations of the character. Her larval stage maintains the appearance of a giant segmented caterpillar. The segments of her body are rounded, and her head is very small compared to the rest of her body. The legs of her larval form are larger and more visible than they have been in past designs. Instead of the large oval-shaped eyes of the imago stage, Mothra's larval stage has much smaller blue eyes. Mothra's larval stage possesses several bioluminescent patches; when Mothra is calm and in her Benevolent Form,[12] she emits a soft blue light. When she feels threatened and poised to attack in her Defensive Form,[13] she emits a red light.

Mothra's imago stage has a segmented insect-like body, with six legs and two wings. Her legs are considerably different from those of past Mothra designs, which are typically small and equally-sized, with clawed bird-like feet. The Monsterverse Mothra has two long hind legs with two joints and two clawed toes. She has four forelimbs, two on each side of her body, with one large pair and one smaller pair. Her forelimbs are longer and more muscular than those of past designs, and end in large hooked claws. Mothra's head is comparatively smaller than it usually is, though it retains her traditional large blue eyes, which are oval-shaped rather than circular. White fur surrounds her eyes, with some brown-orange fur on her forehead which appears to also cover the rest of her body. She possesses two large white antennae which typically lay flat against the top of her head. Mothra has two gigantic compound wings each composed of two segments: a larger segment near the front of her body and a smaller segment toward the rear. The wings possess intricate patterns with the character's traditional orange, yellow, black and white coloration, which can emit bioluminescent glows that shift in color. There is a circular pattern on both sides of the front corners of Mothra's wings, as is the case with her previous designs. According to Godzilla: King of the Monsters director Michael Dougherty, these circles are meant to represent Godzilla's eyes, demonstrating a connection between the monsters.[14]

In Godzilla x Kong: The New Empire, Mothra's imago stage appears largely identical to her appearance in Godzilla: King of the Monsters, but she appears to now have thicker fur with a much brighter orange coloration and white stripes. When using her pulse attack, blue bioluminescent spots appear throughout her body, including around her mouth, chest, eyes, and on the tip of her antennae, as well as a round pattern on her forehead that is only visible when these spots glow.*