Hetaerina pilula Calvert 1901

Hetaerina pilula Calvert. Poptun, in small clearing in gallery forest along large pool in Rio San Pedro, 8: 30 to 10 pm, April 16, THH+IJC (178), 2 ♂. According to the collectors, the river is a succession of deep (to 10 ft) and clear pools with narrower and swifter reaches, some with rapids of small size over limestone rocks.

This is apparently the first record of this species from the Yucatan Peninsula.

Hetaerina pilula, Plesiallotype Female (fig. 3). A female, collected with the two males of pilula, was initially identified as H. macropus according to Calvert’s (1901) key. It differed from macropus in several characters, notably in the presence of two spines on the dorsoapical margin of abdominal segment 10, one on each side. These spines are shorter and more slender than the spine which continues the middorsal carina. Comparison of the female with the description of the male of Hetaerina pilula indicated that this was the undescribed female of that species. The specimen was sent to Calvert for an opinion; his reply (August 8, 1957) contains the following: “Your Guatemala female does not differ more... from the description of pilula male than do females of macropus from macropus males; bearing this in mind I think it would be safe to call it pilula."

The female differs from the description of the male (Calvert, 1901, pp. 33-34) as follows:

Head with nasus with a cupreous metallic reflection, vertex metallic dark green with a coppery-yellow reflection.

Prothorax and thoracic dorsum without coppery-red reflection; a narrow metallic green band along the thoracic carina, widened posteriorly to the humeral suture; a metallic green band on each of the mesepimeron, metepisternum, and metepimeron, that of mesepimeron interrupted posteriorly at three-fourths its length; yellow humeral stripe four to five times wider than the dark brown of the same side of the thoracic dorsum.

Abdomen with a small dorsolateral metallic green spot on segment 1; an elongate dorsolateral green spot extending one-half the length of segment 2; segment 10 with middorsal carina extended and elevated as a slender black spine; two dorsoapical spines on segment 10, one on either side of the middorsal spine, one-half as long and more slender than middorsal spine; ventrolateral apical spines (2 on left, 3 on right) and ventroapical spines, one on each side, as long as the two dorsoapical spines.

Appendages nearly as long as segment 10, conical, acute; genital valvules extend to ventral apex of tergum of segment 10, apical half of inferior margin denticulated.

Stigma obscure in color, surmounting less than one-half cell on all wings; tip of each wing unicolorous with rest of wing, not brown; coppery-red metallic reflection on longitudinal veins from Ri to lower sector of arculus and outward to beyond nodus, otherwise no coloring of the wing to represent the coloring of the base of the wing in the male; median cross veins, 6 in forewing, 7 in hindwing (vs. 9 in male); quadrilateral crossveins, 6 in forewing, 5 in hindwing (vs. 7-9 in male); antenodal crossveins, 23 in left forewing, 21 in right forewing, 22 in left hindwing, 23 in right hindwing (vs. 22 in male).

Abdomen, 34 mm; hindwing, 30 mm

The plesiallotype female, labeled, “ Guatemala: Department Peten, Poptün, April 16, 1956, I. J. Cantrall and T. H. Hubbell, #178,” is deposited in the type collection of the University of Michigan Museum of Zoology.

The following modification in Calvert’s key (1901, p. 21) will permit separation of macropus and pilula females.

f. Pterostigma, if present, obscure in colour.

fi. A dorsolateral apical spine on each side of spine which continues the middorsal carina................................................................................................................ 9. pilula

f-2. No dorsolateral apical spine on each side of spine which continues the middorsal carina.........................................................................................................10. macropus