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These images follow immature male (crawler) images in a series (linked below) documenting the development of a scale insect infesting the pinyon (Pinus edulis) tree in the southeast corner of the Federal Credit Union parking lot on the Corner of Sherman Ave. and Chanute St. (Albuquerque East 7.5 minute quadrangle), Kirtland AFB, Bernalillo Co. NM.

I found extensive masses of the cocoons formed by the immature males after their decent from the pinyon in thick mats of decaying detritus under the tree and a nearby juniper bush. Each cocoon consists of an oval-shaped jumble of white resin fibers about 2 mm long and 1.5 mm in diameter surrounding the prepupa. The fibers are identical in appearance to those secreted by the adult female for its egg mass, but form a more compact and symmetrical structure. The fibers are somewhat sticky, so cocoons formed next to each other adhere. Thousands of cocoons crowded together in some places bound the otherwise loose detritus such that I was able to lift out clumps. A few disturbed cocoons within such a clump are shown above. The fibers have been pulled away to expose the prepupae within, which are otherwise difficult to see. The prepupae are, however, easily seen within their undisturbed cocoons if submerged in ETOH. This implies that the fiber resin itself is clear and has an index of refraction similar to ETOH.

Subsequent images in this set are of a prepupa temporarily immobilized for the stacked imaging sequence by exposure to acetone vapor for several minutes. The last three images are ventral views of increasingly higher magnification, ending with a close-up of the meso and metatarsi. The tarsi each have one curved pointed claw. They also have another curved projection (likely a second claw) and a straight stalk each terminating with what appears to be a white spongy pad. Such pads on arthropods are usually adhesive structures for sticking to hard smooth surfaces. The first stage larva crawlers tenaciously adhere to such surfaces. One can just make out similar pads in their ventral view. These are difficult to see due to the stage's much smaller size.

I noticed under a dissection microscope that the cocoon clumps I collected on Nov 11, 2014 had a few immature male crawlers still looking for a place to cocoon. I did not collect any at the time (their images are from 2015) because they appeared identical to the prepupae within their cocoons. There is no moult between the immature male crawler phase and the cocooned prepupa phase. However, McCambrdge and Pierce 1964(1) state, "Although the immature resemble the prepupae, the latter have wing pads and more pronounced eye spots". More generally, one can see that future adult features are more apparent under the integument after the male has developed for a couple weeks within its cocoon. A small percentage of the prepupae within their cocoons had already moulted into full pupae at this time (next image set). No crawlers were observed from another sample collected on Dec 16, 2014, and most of the cocoons contained pupae.

This image is from a CombineZP processed stack of 200 images with a 22.6 µm step taken with a Mitutoyo M Plan APO 5×/0.14 ∞/0 mm microscope objective + Nikon 135 mm F2.8 AIS telephoto lens + Nikon D300 camera (magnification 3.375×; technique described here).

Phases of development: