PROCEEDINGS OF THE Entomological Society of Washington VOL. 35 APRIL, 1933 No. 4 RHABDOTHRIPS ALBUS, A NEW GENUS AND SPECIES OF THYSANOPTERA FROM PANAMA. By J. Douglas Hood, University of Rochester. The curious insect described below was sent for determination by Mr. John R. Johnston of the United Fruit Company. The types are in my collection. RHABDOTHRIPS gen. nov. (pd/i5os, a rod or stick; Opiip^ a wood worm.) Body and all appendages very slender. Major seta; very large and heavy, pinnatifid apically. Head moderately long, with one pair of enormous setae between the ocelli; vertex not produced beyond frontal costa. Antennae nine-segmented, with a dorsal U-shaped trichome on segment 3 and a similar ventral one on segment 4. Maxillary palpi two-segmented; second segment narrowed in distal half or more. Prothorax with one very large bristle at each anterior angle and two at each posterior angle. Wings very narrow; anterior vein almost completely fused with ambient vein along fore margin; posterior vein represented briefly at middle of wing but partly fused with anterior vein and ambient at or near either end, these fusions perhaps representing cross veins; two rows of large, heavy bristles similar in structure to interocellars and pronotals borne by the fused veins, one row inclined cephalad and the other caudad; fringing hairs sparse and weak. Abdomen with four pairs of similar enormous bristles on segment 9 and two pairs on segment 10. Genotype. — Rhabdothrlps albns sp. nov. This genus undoubtedly finds its closest relative in Coreniothrips Hood, with which it agrees in the possession of the exceedingly stout and apically divided bristles which have suggested the generic name. Both genera are related to Scolothrips Hinds, and all three are probably predacious. F"rom Coremothrips this new genus differs in that (a) the vertex is not prolonged forward to cover the frontal costa when observed from above, (b) there is but one pair of enlarged cephalic setse, interocellar in position, and (c) the anterior angles of the pro-notum bear one pair of large bristles instead of two, the inner pair being wanting. Rhabdothrips is clearly the more primitive of the two genera. It is interesting to note that in it the midlateral and anterior marginal seta? of the pronotum are moderately well developed, and that one of these two pairs — probably the anterior marginal — is quite likely the source of the additional pair of monstrous setae found on the pronotum of Coremothrips. IVPR 2.5^933
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