Described from four females, this species has not been studied by the present authors. A yellow species, with no sternal discal setae, it differs from T. palmi in having only three setae on the lateral margins of the second abdominal tergite.
The genus Thrips is the second largest genus in the Thysanoptera, and currently includes, worldwide, about 285 species. All members of the genus lack ocellar setae I on the head, and they all have ctenidia on tergite VIII posteromesad to the spiracles. Other characters, such as number of antennal segments, number of setae on the fore wing veins, and number of discal setae on the sternites are variable between species (Palmer, 1992; Mound & Masumoto, 2005). T. helvolus has been compared to two other North American members of the genus (Nakahara, 1994: 67), including T. heraclei.
Thrips helvolus Nakahara
Presumably Western USA