Science Below the Belt, of, Just Hangin', with Matt MAcGown

Science Below the Belt, of, Just Hangin', with Matt MacGown

Platygaster abicollis MacGown and Osgood

Platygaster, the abicollis group, generalized view

This is a revised and remodelled Platygastrid Sketchbook page, restarted in October, '06. I had taken the original site down earlier, because it had gone far astray into complex details of acetabular buttons, glossal sensilla, and detailed anatomy of wasp tongues in general.

Things were getting out of hand! Something had to be done. Thus - I eradicated the site.

The following key will place 98 percent of any platygastrid found in the United States to genus. It's a simple version that I've used for decades. For a comprehensive key to the rest of the world fauna, one is welcome to pick up a copy of Masner and Huggerts World Review and keys to the genera of Inostemmatinae. Only, of course, Platygastrinae do not belong in the Inostemmatinae. Inostemmatinae belongs as a subfamily separate from Platygaster.

There are several as yet undescribed genera, which I will illustrate but not attempt to descibe in this sketchbook. Those require a lot more specimens and study, and I see no hurry to do it.

Generic Key To Platygastrinae in the United States

1. Scutellum distinctly modified with dense tufts of setae or with an apical, gouged out area filled with scale like pubescence……………………………………………………..2

1’ Scutellum not so modified, or with a lighter, more uniform covering of pubescence, or terminating in an awn or long spine……………………………………………………….4

2. Female abdomen with 4 tergites; scutellum densely pubescent, uplifted in side view…

……………………………………………………………………..…Metanopedias Brues

2’ Female abdomen with 6 tergites; scutellum more oval in side view…………………..3

3. Head cubical, full behind the eyes in top view, usually with coarse sculpture (smooth in an undescribed California sp.); scutellar pit filled with scale like pubescence………….

…………………………………………………………………………...Isocybus Foerster

(note: according to my recent observations, I doubt this belongs in Platygastrinae, but am not prepared to move it yet).

3’ Head more elliptical or oval in top view,scutellar pit with a dense brush of stiff pubescence………………………………………………………………Trichacis Foerster

4. Scutellum low and subtriangular in top view, evenly covered with appressed pubescence; propodeal lamellae arc like, closely approximated but not fused; pronotal collar with a deep groove running its entire length; last 2 segments of the female antennae very closely approximated………………………………….Amblyaspis Foerster

4’ Scutellum not as above, or, if moderately so, then propodeal lamellae distant by at least their own width, or scutellum terminating in a short to long spine; lst 2 segments of the female antenna not closely approximated……………………………………………..5

5. Thorax extremely compressed in top view; tergite I separated from T – II; head much wider than thorax, scutellum with a short terminal awn; abdomen pendulous…………….

……………………………………………………………………….Piestopleura Foerster

5’ Specimen more robust, may be depressed in side view, or, if as in Synopeas maculipes (Ashm.) appearing quite compressed in top view, then with a ventral pit at the lower corner of the pronotum (difficult to visualize), and T – II fused with T – I. ……………..6

6 (5) Tergites I and II of the abdomen fused in both sexes; scutellum usually with a terminal awn or spine; pronotal collar with a ventral pit or depression…………………..

…………………………………………………………………………Synopeas Foerster

Subgenera:

a. Abdomen beyond T – II drawn out into a long, narrow tail …………………..

………………………………………………Dolichotrypes Crawford and Bradley

a’ Abdomen not prolonged into a narrow tail…………………………………….b

b. Sternite II of the female swollen, pendulous, III to VI narrowed…………

………………………………………………………………...Sactogaster Foerster

b’ Female abdomen not unusually modified…………………...Synopeas Foerster

6'. Abdominal tergites I and II distinctly separate in both sexes, scutellum with (Leptacis) or without spine (Platygaster and it's relatives)..................................................................................7

7. Tergite I (petiolus) distinctly shorter than broad to quadrate (or, if elongate, teh scutellum unadorned); scutellum without spine; propodeal lamellae widely separated by at least their own width; male antennal segment IV (A-IV) with interior tyloid .............................8

7'. Petiolus distincly elngate, scutellum armed, propodeal; lamellae closely approximated (Figs. 30 - 35) ..................Leptacis Foerster

8. Notaulices parallel, marginal sclerite of scutellum high and smooth, delicately sulptured species .......................... Euxestonotus Fouts

8'. Notaulices convergent at the scutellar margin ......................... 9

9. Mesoscutum flat in side view, without trace of notalices ..............

.................................................................. Anopedias Foerster

9'. Mesoscutum robust in top view, or if flat (some Platygaster spp.), then with notaulices.................................................... 10

10. Interantennal projection large, sharply pointed, notaulices extending the full length of the mesoscutum; male A-IV greatly enlarged, with large, diagonal club - like tyloid (Figs. 17 - 20) .......

..........................................................Eritrissomerus Ashmead

10'. Internatennal projection blunt opr concave at the tip, sometimes very small and inconspicuous, notaulices variable, male tyloids not at all as above..........................................................................11

11. Female abdomen reduced to 5 segments, terminating in a long tail (Figs. 14 - 16)........................................Gastrotrypes Brues

11'. Abdomen not reduced, 6 segmented in females and 7 in males, but maya be drawn out into a long tail in females (Platyaster compressiventris, prolata, etc.,) (Figs. 8 - 12) .........................................................Platygaster Latreille.


				*Science Below the Belt, of, Just Hangin', with Matt MacGown*



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