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Tray System for Dissected/Disarticulated Insects


Traditionally, disarticulated or dissected insects have been stored in vials filled with ethanol, or microvials (genitalia vials) filled with glycerin or other preservatives. The former necessitates vigilance over the alcohol level and the latter makes subsequent removal of parts from the microvial difficult and possibly dangerous to the structures being removed. There is also the danger of dissociation of dissected parts from the remainder of the pinned insect.

The Watrous tray (from a system conceived by Larry E. Watrous) permits the storage of dissected parts in a manner useful to the systematist, enables worry-free long-term storage in standard glass covered drawers, and allows the dissected materials to be stored and curated along with any traditionally prepared dry material.


Quentin D. Wheeler
Department of Entomology
Comstock Hall
Cornell University
Ithaca,NY 14853-0999 USA
Tel (607) 255-8050
Fax (607) 255-0939

Pierre R. Fraissinet
Department of Entomology
Comstock Hall
Cornell University
Ithaca, NY 14853-0999, USA
Tel (607) 255-8050
Fax (607) 255-0939

Illustration: Frances L. Fawcett

Publication: 1992



The tray is constructed of a standard size drawer unit tray (ca. 109mm long X 28mm wide X 41mm high) modified with polyethylene foam inserts designed to hold a glass microcup as well as a pinned specimen (Fig. 1).

Figure 1. Cross section of a Watrous tray.

Dissected parts are stored in the microcup in glycerin or a glycerin/glycerin jelly mixture, and the cup is then covered with a standard microscope slide to prevent dust accumulation and spillage. The glass slide is held in place by two insect pins inserted into the polyethylene foam, and pushing down the slide at its end. Any remaining dry parts, as well as original labels, may be stored at the deep end of the tray, held by a pin in the traditional manner.

Materials Tools Supplies

  • Borosilicate glass shell vials, 2dram, ca. 17mm outside diameter
  • Cork borer, ca. 17mm
  • Glue gun and hot melt adhesive
  • Microscope slides
  • Paperboard drawer unit trays
  • Polyethylene foam plank, 3/8in x 24in x 36in
  • Insect pins, black, non-corrosive, #2 (for securing slide & insect)


  • Bunsen burner
  • Glass cutter
  • Heat-insulated gloves
  • Protective eyewear
  • Tongs or forceps


Polyethylene Foam Base

  1. Cut 3/8in polyethylene foam plank into strips ca. 1in wide.
  2. Cut the foam strips into sections that are 3in long and 41/8in long. Cut two 3in long pieces for every one 41/8in long piece.
  3. In half of the 3in foam pieces, punch a 17mm hole in the center with a cork borer.
  4. With a hot glue gun, adhere the longer foam piece to the bottom of the tray.
  5. Adhere an unpunched 3in foam piece on top of the first foam layer.
  6. Adhere the punched foam piece on top of the second layer.


  1. Purchase 2dram vials that are cut and polished commercially, or using the glass cutter, cut the 2dram vials to a height of 10mm.
  2. Wear protective eyewear and heat-insulated gloves, and polish the cut edge of the vials by carefully holding the cup with tongs or a large forceps over a Bunsen burner flame and turning until the edge is no longer sharp.
  3. Allow the vial to cool.


Although the hygroscopic properties of glycerin will prevent complete desiccation of preparations, levels in the microcups should be periodically adjusted. Preparations involving glycerin jelly, useful for short-term research storage, will dry over extended periods of time (10-20 years), and so should not be considered for permanent storage of disarticulated insects.

Adapted From

Wheeler, Q. D. 1987. Watrous trays: a storage system for disarticulated and dissected insects. Curator, 30(1):73-76.

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