Records of the Western Australian Museum 17: 267-275 (1995). 
Revision of the Australian wasp genus Macrothynnus Turner 
(Hymenoptera: Tiphiidae: Thynninae) 
G.R. Brown 
Museum and Art Gallery of the Northern Territory, GPO Box 4646, Darwin, NT 0801 
Abstract - The thynnine genus Macrothynnus is revised. Both M. insignis 
(Smith) and M. simillimus (Smith) are redescribed together with two new 
species, M. mustus and M. watherooensis. M. molitor (Smith) is removed from 
synonymy with M. simillimus and M. ioleius Montet is synonymised with 
Onchorhinothynnus xanthospilus (Shuckard). 
INTRODUCTION 
Macrothynnus was erected as a subgenus of 
Thynnus Fabricius by Turner in 1908. Five species 
were included but only T. insignis Smith and T. 
simillimus Smith (type species) were retained when 
the subgenus was raised to generic rank (Turner 
1910). There has been no subsequent work 
published on this genus. 
Terminology follows Turner (1908) and 
Snodgrass (1941). Abbreviations: AM, Australian 
Museum, Sydney; ANIC, Australian National 
Insect Collection, CSIRO, Canberra; BCRI, 
Biological & Chemical Research Institute, N.S.W. 
Agriculture, Rydalmere; UCD, University of 
California, Davis; NTM, Northern Territory 
Museum, Darwin; SAM, South Australian 
Museum, Adelaide; WAM, Western Australian 
Museum, Perth; Tl-7, metasomal tergites 1-7; SI- 
6, metasomal sternites 1-6. 
SYSTEMATICS 
Genus Macrothynnus Turner 
Thynnus (Macrothynnus) Turner, 1908: 194; Turner, 
1910: 44; Given, 1954: 47; Salter, 1954: 302. 
Type species 
Thynnus ( Macrothynnus ) simillimus Smith, by 
original designation. 
Remarks 
Although some of the diagnostic characters used 
by Turner (1908, 1910) are of dubious diagnostic 
value (Salter, 1958), the genus can be recognised in 
the males by an epipygium (tergite 7) which is 
produced into a small subapical plate and which is 
longitudinally carinate dorsally and transversely 
carinate posteriorly (Figure 1), and the absence of 
spines on sternite 6. It is distinguished from 
Zaspilothynnus by the absence of spines on sternite 
6, from Guerinius by the presence of epipygial 
(tergite 7) carinae, and Hemithynnus and 
Megalothynnus by the presence of a subapical plate. 
In the females, tergite 2 (Figure 2) is transversely 
carinate and the pygidium (tergite 6) is subovoid 
with an almost flat posterior surface which is 
transversely carinate dorsally becoming 
longitudinally carinate ventraliy and medially, and 
which is at most slightly excavate dorsally. These 
character states distinguish females from 
Zaspilothynnus and Guerinius which have the 
pygidium strongly excavate laterally, Hemithynnus 
which has the pygidium laterally spined, 
Oncorhinothynnus which lacks transverse pygidial 
carinae (apart from a single marginal carina) 
dorsally, and Megalothynnus which lacks 
continuous transverse carinae on the second 
tergite. 
Key to the species of Macrothynnus Turner 
(Note The male of M. molitor and female of M. 
simillimus are unknown.) 
1. Macropterous (males).2 
Apterous (females).5 
2. Antennal prominence, scape, posterior 
margin of pronotum and legs orange; 
tergites almost impunctate with indistinct 
and irregular black marks anteriorly (which 
may be obscured by the preceding tergite) 
[WA]. insignis 
Antennal prominence, scape, pronotum and 
legs black; tergites finely and closely 
punctate, without black marks.3 
3. T1 tuberculate medially above anterior 
truncation.4 
T1 not tuberculate [ACT, NSW]. 
. simillimus 
