Atithasus Foerster, 1868

Taxonomic History / Nomenclature
Atithasus Foerster, 1869: 210. Type species: Atithasus stellarius Davis, 1897 [= Atithasus bimaculatus Ashmead, 1896]. Subsequent inclusion by Davis (1897: 291).
Atithasus bimaculatus (Ashmead, 1896) is the only valid species. It occurs in the eastern half of the USA. Cummins et al. (2011) reported on egg load for this species.
Diagnosis and Relationships
Atithasus is very distinctive. It is readily recognized by the short hind tibial spurs (Fig. 1), the long, deep notaulus, and the weak dorsal portion of the epicnemial carina.

The fore wing areolet is variable: present in only half of 18 wings examined. Those without a fore wing areolet would therefore have to be forced through the key to mesoleiine genera presented by Townes (1970). Townes (1970) also noted that the setae on the hind tibia were “exceptionally strong and dense” (partially visible in Fig. 1 of the description section), but this feature can be found in some other mesoleiine genera as well.

Clypeus short and wide, distinctly bulging (convex) in profile, coarsely punctate; ventral margin blunt, weakly convex (Fig. 2) to truncate (Fig. 3) medially (depending in part on angle of view), rounded laterally; epistomal sulcus narrow, deeply impressed throughout. Malar space very short (female, Fig. 2) to absent or essentially so (male, Fig. 3). Mandible (Figs 2, 3, 5, 6) long; gradually narrowing from base to middle, very slightly expanding to apex; curved; ventral tooth much longer than dorsal tooth; ventral margin carinate. Female with maximum diameter of lateral ocellus a little shorter than distance between ocellus and eye; male with ocelli larger, about equal in diameter to distance between ocellus and eye. Female antenna longer than body, male more nearly equal in length to body (Fig. 1); first flagellomere long and slender, nearly twice length of second in female, shorter in male. Hypostomal carina joining occipital carina a little above base of mandible; occipital carina complete. Epomia variable, absent or present. Dorsal end of epicnemial carina weak, distinctly separated from anterior margin; mesopleuron punctate. Notaulus sharply impressed on anterior declivity, distinct on disk to scutellar sulcus, always well developed, though somewhat variable in depth among specimens. Pleural carina usually complete, usually well-developed (Fig. 7); propodeal carina partly reduced: lateral longitudinal carinae indistinct to absent; petiolar area very broad (Fig. 7), hemispherical, well-delineated throughout by a carina; lateral portion of posterior transverse carina nearly always (90%) distinct, defining posterior lateral fields; median longitudinal carinae sometimes absent, otherwise weak, somewhat irregular and hour glass-shaped between petiolar area and anterior margin of propodeum. Apex of hind tibia completely without comb on posterior side; hind tibial spurs very short, triangular (Fig. 8), not slender as in nearly all other mesoleiines; all tarsal claws apparently simple, not pectinate. Fore wing areolet present in 50% of wings examined; stigma not exceptionally broad, with Rs+2r arising from about basal 0.4. Hind wing (Fig. 1) with first abscissa of CU1 distinctly longer than 1cu-a. T1 (Fig. 9) relatively short and broad in female, a little longer and more slender in male, gradually widening posteriorly; dorsal carinae tall basally, low posteriorly, extending well posteriorad spiracle to or nearly to posterior margin, rounded, never sharp, even basally; basal depression for dorsal tendon attachment broad, deep; dorsal-lateral carina usually sharp and distinct from apex anteriorly to about half distance to spiracle, absent around spiracle; glymma deep, broad basally, narrowing posteriorly. S1 very short about 0.3 times length of T1; spiracle clearly basad midpoint of T1 (Fig. 9). Laterotergites of T2 and T3 completely separated by creases. Ovipositor short, straight, with deep, broad subapical, dorsal notch.

This description is considerably modified from Townes (1970) and based on specimens in the Texas A&M University collection.

1. Atithasus bimaculatus male habi...
2. Atithasus bimaculatus female face a...
3. Atithasus bimaculatus male face and ...
4. Atithasus bimaculatus male clyp...
5. Atithasus bimaculatus female ma...
6. Atithasus bimaculatus female mandible...
7. Atithasus bimaculatus propodeum...
8. Atithasus bim...
9. Atithasus bimaculatus T1...
No referenced distribution records have been added to the database for this OTU.

There are no specimens currently determined for this OTU, or those specimens determined for this OTU are not yet mappable.

This page was assembled by Bob Wharton as part of a larger collaborative effort on the genera of Ctenopelmatinae. Page last updated May, 2015.

This work would not have been possible without the groundwork provided by Ian Gauld’s study of the Australian and Costa Rican faunas, and we are particularly grateful for his assistance in many aspects of this study. We also thank David Wahl of the American Entomological Institute and Andy Bennett of the Canadian National Collection for extended loans of the material used for this study. Matt Yoder provided considerable assistance with databasing issues, and our use of PURLs ( in this regard follows the example of their use in publications by Norm Johnson. Heather Cummins, Caitlin Nessner, Mika Cameron, Karl Roeder, and Cheryl Hyde graciously assisted with image processing, formatting, and literature retrieval. This study was supported by the National Science Foundation’s PEET program under Grant No. DEB 0328922 and associated REU supplement #s DEB 0723663 and 0923134.

This material is based upon work at Texas A&M University supported by the National Science Foundation under Grant Number DEB 0328922 with REU supplements DEB 0723663 and 0923134. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.