Striatoandricus guatemalensis (agamic)

Andricus guatemalensis (Cameron), New Combination

Cynips guatemalensis Cameron, 1883: 71, gall. 
Andricus? mexicana Bassett, 1890: 78 (gall). 
Andricus mexicanus Bassett, Dalla Torre, 1893:91. 
Andricus mexicanus Kinsey, 1920: 308, figs. 25-27 (female, male, gall). New Synonymy. 
Synergus dorsalis Cameron, 1883: 72 (not Provancher, 1888: 398). (female, male). New Synonymy.

Remarks.— Cameron (1883) described the galls of C. guatemalensis which were sent to him from Guatemala. Bassett (1890) described the galls of Andricus? mexicana from galls collected in Mexico. Neither Cameron nor Bassett described what they thought was the gall inducer, although Cameron (1883) described Synergus dorsalis, which he thought was an inquiline in galls of C guatemalensis (see below). Kinsey (1920) was the first to describe the adult gall former, which he obtained by cutting from galls that had been sent to the American Museum of Natural History. Kinsey recognized that the galls he had were the same as those of C. guatemalensis Cameron and also those of Andricus mexicanus Bassett. However, Kinsey did not believe that names based on only the galls were valid as he described Andricus mexicanus as a new species while listing C. guatemalensis Cameron 1883 and Andricus mexicanus Bassett 1890 as synonyms. Thus, A. mexicanus Kinsey is a junior synonym of both C guatemalensis Cameron and A. mexicanus Bassett, and a junior homonym of A. mexicanus Bassett. A new name for Andricus mexicanus Kinsey 1920 would needlessly burden the already confused nomenclature. Both Bassett and Kinsey were correct to assign the species to Andricus and C. guatemalensis is hereby transferred to this genus. 

The holotype of S. dorsalis (in the British Museum (Natural History)) belongs to the genus Andricus and is a synonym of Cynips guatemalensis Cameron. Although the type of guatemalensis is a gall while the type of dorsalis Cameron is an insect and it is desirable to base species of Cynipidae on the insect rather than the gall, we retain guatemalensis as the valid name in the interest of stability. There are two reasons for doing this. First, the name guatemalensis has been associated with a gall-inducing species while dorsalis Cameron has been associated with an inquiline species. Second, retention of guatemalensis simplifies a problem of secondary homonymy between S. dorsalis Cameron 1883 and S. dorsalis (Provancher) 1888.

When Weld (1951) transferred Ceroptres dorsalis Provancher to Synergus, this species became a secondary homonym of S. dorsalis Cameron. However, Weld did not rename S. dorsalis (Provancher) either because he did not know that it was a homonym, or because he knew that S. dorsalis Cameron should not have been placed in Synergus. Weld visited the British Museum (Natural History), after which he synonymized S. filicornis Cameron and S. furnessana Weld (Weld, 1930). It is quite likely that he also examined the type of S. dorsalis Cameron as well. A new name for S. dorsalis (Provancher) is unnecessary as S. dorsalis Cameron is now considered a junior synonym of Andricus guatemalensis Cameron and therefore the two species are no longer congeneric.

A review of the species of Synergus from Guatemala, with notes on Cynips guatemalensis Cameron (Hymenoptera: Cynipidae)