Tachytes melanogaster Pulawski, 2019

Pulawski, Wojciech J., 2019, A Review of the Wasp Genus Tachytes Panzer, 1806 of Madagascar (Hymenoptera: Crabronidae), Proceedings of the California Academy of Sciences 66 (7), pp. 117-135 : 129-130

Tachytes melanogaster Pulawski , species nova

Figures 26–29. NAME DERIVATION.— Melanogaster is derived from two Greek words: μελανός (black, dark)

and γαστήρ (gaster); with reference to the presence of black setae only on this species terga I-V.

RECOGNITION.— Only the female of this species is known. Unlike all other Madagascan species, and like T. nigropilosellus (Cameron) and T. nudiventris Turner from the continental Africa, T. melanogaster has the setae of terga I-V all black (Fig. 27) and directed posteriorly (rather that all golden or silvery on apical depression and diverging posteriorly on the apical depressions of at least terga IV and V). Unlike these two species, the female of T. melanogaster has five rather than six rake spines on the forebasitarsus and the setae of the pygidial plate (Fig. 28) cupreous (rather than black). The postocellar punctures in T. melanogaster are mainly large and sparse, intermixed with smaller and denser punctures (Fig. 26), whereas in T. nudiventris the fine punctures are absent and only the larger, sparse punctures are present ( Fig. 25 ); also, the wing veins are light brown in T. melanogaster , but the costal and subcostal veins are black in T. nudiventris . T. nigropilosellus differs conspicuously in having the erect setae of the head, thorax, and propodeum black (rather than silvery), the wings deep black with violet shimmer (rather than nearly hyaline, with yellow tinge), and by its much larger size (the female length is 23-30 mm, while 14.5-15.0 mm in T. melanogaster ).

DESCRIPTION.— ♀. Head nearly round in front view; minimum interocular distance equal to 0.32-0.34 of the clypeal width and to 1.4 ×of dorsal length of flagellomere I; the latter 2.3-2.4 × apical width. Postocellar punctures mainly large, sparse, intermixed with smaller and denser punctures (Fig. 26). Gena narrow in dorsal view, narrower than in T. panzeri . Sternum II minutely, closely punctate throughout except narrowly impunctate apicomesally in one specimen. Forebasitarsus with five rake spines.

Pronotal collar posteriorly with appressed silvery setae, remaining thorax and propodeum without such setae. Setae of postocellar area about as long as 0.5 × scape; scutum anterolaterally without conspicuous appressed pilosity; scutal setae about as long as 0.4 × scape; sternum II anterolaterally with sparse, inconspicuous erect setae whose length is up to about 2 × midocellar width; longest setae of hindfemoral venter equal to about 0.4 × hindfemur greatest width. Setae of terga I-V all black and directed posteriorly; setae of pygidial plate cupreous (Fig. 28).

Head, thorax, and gaster all black; scape ferruginous (except partly or all black dorsally), fla-

Figures

FIGURE 25. Tachytes nudiventris Turner. Postocellar area of female. FIGURES 26-28. Tachytes melanogaster sp. nov. (26) Postocellar area of female; (27) Female gaster in dorsal view; (28) Pygidial plate of female showing color of setae.