May 2018
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1 Head and body all dark (face yellow in male) ..….………………………………..……… niger
1’ Head and body more extensively yellow …….…………………………..……….……….…. 2
2(1) Fore wing hyaline ………………………………………..………….………..……… iceryae
2’ Fore wing with distinct dark spot on disc …..………………………………….…………….. 3
3(2) Vertex wider, ocelli forming equilateral triangle; malar sulcus present; mid- and hind tarsi dark ……………………………………………………………..….. sp. 1
3’ Vertex narrower, ocelli forming acute triangle; malar sulcus absent; mid- and hind tarsi white, except for apical 1-2 segments ………………… puncticeps
Sp. 1: Sierra (RLZC)
Described Nearctic species and distribution
atriventris Ashmead, 1900: CAN (ON, QC); USA (FL, MA, VA)
iceryae Howard, 1887: USA (CA, DC, FL, KS, LA, MD, MO, NC, SC)
montanus Slosson, 1895: USA (CO, NH)
niger Ashmead, 1900: USA (CA, DC, MA, UT, WA, WI)
puncticeps (Howard, 1885): USA (CA, DC, FL, VA)
vinulus (Dalman, 1820): CAN (PE)
Remarks
Timberlake (1919) presented a world wide key to species that is still good for the described Nearctic fauna. There is a single damaged specimen (UCR) from Yolo County, labelled I. puncticeps, that matches the label data that Timberlake (1919: 190) reported. However, this specimen does not appear to match the original description. But I there are many other specimens from northern California (EMEC, RLZC) that do match the description of this species. A single specimen from Tulare County (CAS) tends to key out to I. niger, but is not as dark – this specimen was recovered from a flume, so perhaps the continued immersion in water resulted in a washed-out coloration. Specimens of I. atriventris key to sp. 1, but in the former F1 and F2 are longer than wide and the malar suture is not darkened, while in the latter F1 and F2 are quadrate and the malar suture is dark. Specimens of I. vinulus do not match anything – they are all dark dorsally, except for two yellow patches at the base of the scutum and across the pronotum.
References
Ashmead, W. H. 1900. On the genera of the chalcid-flies belonging to the subfamily Encyrtinae. Proceedings of the United States National Museum 22: 323-412.
Dalman, J.W. 1820. Försök till Uppställning af Insect-familjen Pteromalini, I synnerhet med afseen de på de I Sverige funne Arter (Fortsättning). Kungliga Svenska Vetenskapsakademiens Handlingar 41: 123-174, 177-182, 340-385.
Howard, L.O. 1885. Descriptions of North American Chalcididae from the collection of the U.S. Department of Agriculture and of Dr. C.V. Riley, with biological notes. [First paper]. Bulletin of United States Department of Agriculture, Bureau of Entomology 5: 1-47.
Howard, L.O. 1887. Report of the entomologist. Report of the United States Department of Agriculture, 1886: 488.
Slosson, A.T. 1895. The season on Mt. Washington. Entomological News 6: 276-280.
Timberlake, P.H. 1919. Revision of the parasitic chalcidoid flies of the genera Homalotylus and Isodromus Howard, with descriptions of two closely related genera. Proceedings of the United States National Museum 56: 133-194.