Chrysidid preparation

Chrysidids must be handled with soft tweezers, paying attention to the fragile articulations of legs and antennas. A good handling zone is the chitinic, strong thorax.

A good preparation of the specimen makes the study and identification easier. For this purpose, avoid a collection of specimens glued in dead position (rolled-up), as well as avoid to pin the specimens through the thorax, as you do in the case of large wasps or beetles. Anyway, if you prefer to pin the specimens, choose a thin pin (preferably numbers 00 or 0) or a micro-pin. In the latter case, the micro-pin (also known as "minuten pins") will be supported by an entomological label, so we think that if the specimen has to be pinned, it's quicker and easier to pin it with the standard entomological pins.

Standard entomological (insect) pins

No. length mm Ø mm 000 38 0.25 00 38 0.30 0 38 0.35 1 38 0.40 2 38 0.45 3 38 0.50 4 38 0.55 5 38 0.60 6 38 0.65 7 52 0.70

 

 

OK, we prefer to glue the specimen on a transparent entomological label, because the specimen remains protected and it is possible to examine its bottom side. You need to find a good glue and a limited range of label sizes, in order to give your collection a good standard.

We suggest the following steps:

• (0) humidificate the specimens (if they are dried);
• (1) prepare the specimens;
• (2) dry them;
• (3) glue them on the entomological labels, and
• (4) complete all with capture labels and with entomological support pin.

 

(0) Humidification - If the specimen is dry (dehydrated) or if you want to re-prepare it, you have to humidificate it in a hermetic jar containing cotton and some water. The time of permanence is variable and you can test the state of mobility of the articulations of the specimen with a fine pin. A fast method of humidification consists in taking a syringe, removing the needle, inserting the dried specimen in the room, partially filling up the syringe with water. Then turn the syringe upwards and press the piston in order to eliminate the air, then, closing the needle-hole with the inch to ensure the vacuum, pull the piston: in a such way the air contained in the specimen is extracted and replaced by water, forcing the humidification of the specimen. Repeat the process 2-3 times.

(1) Preparation - In order to prepare the specimen you need a panel similar to the bottom of the entomological boxes - an expanded closed-cell foam - which allows you to insert/extract pins easily and to hold them in position. A material like that is usually known as Plastazote. Then you need a pair of soft tweezers and a variety of thin entomological pins (measures 000, 00, 0). First of all, if the specimen has the internal abdominal segments still inside, you have to operate with a thin pin to extract the package of the internal segments, in order to determine the sex of the specimen. If you extract the whole genital packet, you need to prepare it, if you are able. The internal segments must be separated and glued under a stereomicroscope. Alternatively, you can leave it a little bit outside of the specimen's abdomen, just for the sex distinction. Or you can extract it and glue it to a label, without any other preparation, for future examination. If you choose this way, simply pose the packet on a second card, drowning it in a drop of resin (Eukitt or Euparal). Then, with the tweezers you have to set the specimen lying down in ventral position, locking it to the panel with 2-3 pins intercrossing the thorax. With other pins you will symmetrically open legs, head, antennas and wings. Legs and wings must be opened not too close to the body, to allow the examination of some diagnostic characters.

(2) Drying - The specimen will rest for various days on the panel in dry atmosphere, which facilitates the evaporation and therefore the dehydration of the tissues. Recently-catched specimens will need more time for the complete dehydration, because they contain internal soft tissues. Once dried - you can test the status of rigidity by using a thin pin #000 to move the wings - you can remove the locking pins, paying attention during the extraction and avoiding an elastic return of the pin against the rigid fragile appendages.

(3) Entomological label - The dried specimen is then glued on an entomological carrying-object label of adequate dimension and possibly similar to the other used for the specimens of similar dimension. To this purpose, it is useful not to have too many label sizes, but to have one-two standard measures only: we think that the 6x16mm and the 8x22mm labels are enough to fit the average body sizes of Chrysidids. A traditional entomological label is a precut card, generally stamped with some guidelines, but you can also use cards manually cut from transparent plastic sheets, which facilitates the examination of the ventral face of the specimen. The glue must be easy to buy and easy to remove from the specimen through the humidification: a vinilic glue (i.e. Vinavil) is suggested.

(4) Capture label - The prepared specimens need now to be completed with the capture labels, with the following data: collection place (Country, State, Region, City, locality, etc.), significant geomorfologic element (lakes, forests, rivers, etc), coordinates (if known), date (using an international convention for which the month is in Roman numbers, i.e. XII (= 12) for December), name(s) of collector(s) (i.e. "leg. C. Darwin" or "C. Darwin coll.", depending on the Latin or English terminology). On another label you may add some notes about your field observations (i.e. on Daucus flower). Avoid an excessively personal simbology and personal numerations, because one day that specimen could be exchanged with other entomologists or be donated to a Museum: cryptic information in the labels could be a problem for the future researchers. All these data could be written on more cards, and possibly only on the upper surface.