Mesorhaga

Bickel, Daniel J., 2007, The Mesoamerican Mesorhaga (Diptera: Dolichopodidae), with a taxonomic conspectus of the New World fauna, Zootaxa 1411, pp. 47-67 : 50-51

Nearctic Mesorhaga

The Nearctic fauna is poorly documented and badly in need of both collection and revision. A major problem

is that many Nearctic species are known only from females. The current keys ( Parent 1929, Robinson 1964)

are unreliable, since they are based on a mix of male and female characters (leg color, for example, can be sex-

ually dimorphic in Mesorhaga ).

albiciliata Aldrich 1893: 48 (USNM) ( Aptorthus ) U.S.A.: New Jersey, Georgia, North Carolina.. This species has also been recorded from Puerto Rico ( Robinson, 1970).

borealis Aldrich 1893: 49 (USNM) ( Aptorthus ) U.S.A.: Minnesota. (described from female only).

caerulea Van Duzee 1930: 1 (AMNH, examined) U.S.A.: Connecticut. The unique holotype is a female, not a male as described by Van Duzee.

caudata Van Duzee 1915: 94 (CUIC, examined) U.S.A.: Georgia. The male postabdomen of this species is illustrated here ( Fig. 4 c, d), as a supplement to Van Duzee’s original description. As noted in the original description, the cercus is curved, and yellow with long yellow setae.

clavicauda Van Duzee 1925a: 154 (CAS, examined) U.S.A.: Michigan, Illinois, New Jersey. I have seen additional specimens from Burlington Co., New Jersey. This species is a member of the otherwise Neotropical isthmia species group.

flavipes Van Duzee 1932a: 9 (AMNH, examined) U.S.A.: New York. Van Duzee discussed the similarity of M. flavipes and M. varipes , and I suspect they are conspecific.

jucunda Becker 1922: 377 (syntypes: TMB, destroyed; ZMHB, examined). Paraguay & U.S. A.. Becker provided a comprehensive description and wing illustration of Mesorhaga jucunda based on a male-female pair from Paraguay: Asuncion (TMB, destroyed) and a single female from Georgia, U.S.A. (ZMHB, examined). However, it is extremely doubtful that specimens from these distant localities would be conspecific, and although the description would enable recognition of new Paraguayan material (for example, the male has the last three tarsal segments of leg III widened), the species is now represented by a female syntype from the U.S. A.., which I cannot identify. Therefore, without evidence to the contrary, this species should be regarded as solely Nearctic, and South American specimens close to Becker’s description should be described as new.

nigripes Aldrich 1893: 49 (USNM) ( Aptorthus ) U.S.A.: California (described from female only). Van Duzee (1917:124) described a male of this species, based on Californian specimens.

[ ornatipes Van Duzee 1932b: 184 . Cuba. Robinson (1964) cites a questionable record from Georgia, USA; see above under Neotropical Mesorhaga ].

pallidicornis Van Duzee 1925b: 178 (CAS, examined) U.S.A.: Ohio; Manitoba., Ontario, Midwest U.S. A, south to Texas.

tricorniflavrai Gunther 1982: 4 (USNM) U.S.A.: Illinois.(syn. Bickel 2002)

Mesorhaga pallidicornis is rather common and widespread in central North America, and has distinctive pale yellow setae on the head and thorax, coxa I and all legs yellow, and a black scape and pedicel that contrasts with a bright yellow first flagellomere. I have seen additional specimens from Indiana: New Harmony, viii.1967 (CAS); Michigan: South Haven, vi (USNM); Nebraska: Thomas Co., vii.1967 (CAS), Hooker Co., vii (USNM); Texas: Wheeler Co., vi (USNM).

townsendii Aldrich 1893: 50 (USNM, examined) ( Aptorthus ) U.S.A.: Arizona. (described from female only).

varipes Van Duzee 1917: 123 (MCZ, examined) U.S.A.: Massachusetts. (see above under M. flavipes ).

Figures

FIGURE 4. Mesorhaga minatitlan n. sp.: a. hypopygium, left lateral. M. nayaritensis n. sp.: b. hypopygium, left lateral. M. caudata Van Duzee: c. male postabdomen, left lateral; d. male postabdomen, dorsal.