ABSTRACT-We document evidence of endophytic oviposition on fossil compression/impression leaves from the early Eocene Laguna del Hunco and middle Eocene Río Pichileufú floras of Patagonia, Argentina. Based on distinctive morphologies and damage patterns of elongate, ovoid, lens-, or teardrop-shaped scars in the leaves, we assign this insect damage to the ichnogenus Paleoovoidus, consisting of an existing ichnospecies, P. rectus, and two new ichnospecies, P. arcuatum and P. bifurcatus. In P. rectus, the scars are characteristically arranged in linear rows along the midvein; in P. bifurcatus, scars are distributed in double rows along the midvein and parallel to secondary veins; and in P. arcuatum, scars are deployed in rectilinear and arcuate rows. In some cases, the narrow, angulate end of individual scars bear a darkened region encompassing a circular hole or similar feature indicating ovipositor tissue penetration. A comparison to the structure and surface pattern of modern ovipositional damage on dicotyledonous leaves suggests considerable similarity to certain zygopteran Odonata. Specifically, members of the Lestidae probably produced P. rectus and P. bifurcatus, whereas species of Coenagrionidae were responsible for P. arcuatum. Both Patagonian localities represent an elevated diversity of potential fern, gymnosperm, and especially angiosperm hosts, the targets of all observed oviposition. However, we did not detect targeting of particular plant families. Our results indicate behavioral stasis for the three ovipositional patterns for at least 50 million years. Nevertheless, synonymy of these oviposition patterns with midMesozoic ichnospecies indicates older origins for these distinctive modes of oviposition.

The nests of Cadeguala albopilosa (Spinola, 1851), Diphaglossa gayi Spinola, 1851, Ptiloglossa tarsata (Friese, 1900), Ptiloglossa matutina (Schrottky, 1904) and Zikanapis tucumana (Moure, 1945) (Colletidae, Diphaglossinae) from Argentina and Chile are described herein. They show similar features to those of other Diphaglossinae: they consist of a main tunnel, cells disposed radially, isolated or in pairs, and connected to the main tunnel by laterals ones. Main tunnels are mostly vertical in species nesting in soil surface but horizontal to inclined in D. gayi, which nests in banks. Cells are vertical with curved necks. The cells of C. albopilosa show less curved necks (less than 90°), whereas in the remaining four species the cell neck is highly curved (90° or more). Cells of P. tarsata have a spiral earthen closure and a wad cottonlike material, whereas in P. matutina only had the last one. In the remaining studied species any type of closure were found. Cocoons of C. albopilosa and P. tarsata are coriaceous showing a closure composed of three disks. Zikanapis tucumana and possibly P. matutina showed dim-light foraging. The remaining species are diurnal. The climate in their nesting sites is highly diverse, ranging from 8°C to 20°C in mean annual temperature, and from 250 mm to 3000 mm in mean annual precipitation. Only C. albopilosa and, to a lesser extent, Z. tucumana nested gregariously. Zikanapis tucumana and P. tarsata were observed visiting flowers of Solanum.

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