Leptothrips oribates Hood

Leptothrips oribates Hood, 1939: 205 .

Leptothrips oregonensis Hood, 1939:213; Synonymised by O’Neill, 1972: 272. Leptothrips brevicapitis Johansen, 1987: 52 . Syn. n.

Described from Colorado, Arizona and New Mexico, with one synonym from Oregon, specimens of this species have also been seen from Nevada and California . It is closely associated with species of Pinus, and has been taken several times from immature pine cones. It is distinguished from pini, with which it shares this host association, by the presence on antennal segment IV of four sense cones. Both species lack pronotal sculpture and have the fore wings pale at the base, but the available distribution records suggest that they are adapted to rather different ecological conditions, with pini mainly from the Florida area, but oribates from the Western states . Johansen described brevicapitis from a few specimens associated with Pinus from California and Arizona . He stated that these specimens have the eyes prolonged ventrally, in contrast to those of oribates . However, the difference between the dorsal and ventral surfaces in the holotype (see Fig. 73 in Johansen, 1987) is trivial, and involves a difference of no more than the diameter of a single ommatidium. The extent to which the eyes are longer ventrally than dorsally in the available specimens of oribates is here interpreted as being associated with the orientation of the head in slide-mounted specimens (see discussion above). More than 40 specimens of oribates have been studied from various sites in California (in ERMR); two of these were noted to have only three sense cones on segment IV of one antenna (but not on both), and in all of them segment IV lacked a small ancillary sense cone (= sensillum coeloconicum) on the external surface.