Download high resolution image here.

I found the beetle with these phoretic deutonymphs attached under the bark of a decaying pine log on Tree Spring Trl. (No. 147), 9300 ft, Sandia Crest 7.5’ quadrangle in the Sandia Mountains, Bernalillo Co, NM. Identification is based on similarity to other images posted for the genus such as this. Expert confirmation is appreciated.

Views of the host are posted here:



The cluster of five mites shown is visible on the host's right rear elytron. The orientation is chosen to be the same as the host. The mite's are seen upside down here (the legs extended in the anterior direction).

The dorsal shield has a globular textured surface. Initially, I thought the shield might be transparent and the globules were internal structures. So, I processed a subset of 10 sequential images of the original so that only a 10 µm thick planar layer is in focus in the final image. This image, which shows a different layer of each of the five mites due to their varying distances from the objective, shows that internal structures do not come into focus; the mite is only translucent. The globular structures visible in the dorsal view are, therefore, part of the dorsal shield.

The mites attach to their host by a secreted adhesive, remnants of which can be in the ventral views linked. Two samples are provided with mites mounted by their dorsal surfaces to clear (euparal) and black (nail polish) adhesive beads on the end of 80 µm tungsten wires to show them with and without partial backlighting, respectively. External illumination is highly diffuse, except for a black velvet backdrop. Backlighting in the first case is due to refraction through the euparal bead. A cluster of eight round structures on the back half of the ventral surface is visible in these views are part of the attachement organ, based on Fig. 20 of the idtools.org Histiostoma fact sheet

This image is from a CombineZP processed stack of 122 images with a 0.9 µm step taken with a Nikon BD Plan Apo 40X/0.80 210/0 mm microscope objective + adapter/extension tube + Nikon D300 camera.