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Calaphidinae : Panaphidini : Myzocallis castaneae


Myzocallis castaneae

Chestnut gay louse

On this page: Identification & Distribution Other aphids on the same host

Identification & Distribution

All adult viviparae of Myzocallis castaneae are alate. The species was given the English name 'chestnut gay louse' by Fitch (1856) as he felt "their bright, lively colors, and their long slender antennae and legs render them the prettiest objects belonging to the aphis family". They are coloured yellow and lack a longitudinal dark spinal stripe on the head and pronotum (cf. Myzocallis castanicola in Europe and western North America, which has a longitudinal dark spinal stripe on the head & pronotum). The anterior frontal hairs of the head are long and finely pointed, 2.0 or more times the basal diameter of antennal segment III (cf. Myzocallis nanae in Florida & Myzocallis castaneoides in eastern USA, both of which have shorter, often capitate, frontal hairs). Antennal segments III-VI are uniformly black (cf. Myzocallis tissoti in Florida, where the antennal segments IV, V and the base of VI, are pale at the base and dark at the apex). Antennal segment III bears 7-10 secondary rhinaria. The terminal process is 2.9-3.6 times as long as the base of antennal segment VI. The apical rostral segment (RIV+V) is 0.93-1.00 times the length of the second hind tarsal segment (HTII). The forewing has the pterostigma with a black spot at its base and a line of pigment following its posterior margin. Wingvein Cu1b and base of vein Cu1a are black-bordered. The tibiae and tarsi are coloured black, but the femora are pale. The body length of adult Myzocallis castaneae alatae is 2.1-2.6 mm.

Both images above copyright Tom Murray under a Creative Commons Attribution License.

Myzocallis castaneae feeds on the undersides of leaves of American chestnut (Castanea dentata) and possibly other Castanea spp. (see below) in North America. There is no host alternation. Essig (1917) observed that in California this species was "often in large enough numbers to cause a general smutting of the trees" and reported that that sexual forms were taken in October. Unusually for Myzocallis species, as the second picture above indicates, Myzocallis castaneae is sometimes ant-attended. The chesnut gay louse is found in Canada and the United States.


Other aphids on the same host

Although Blackman & Eastop in Aphids on Worlds Plants, give additional unspecified Castaneae spp. as hosts in the text, Castanea dentata is given as the sole host in the listings.

Blackman & Eastop list 5 species of aphid as feeding on American chestnut (Castanea dentata) worldwide, and provide formal identification keys (Show World list). Of those aphid species, Baker (2015) lists 1 as occurring in Britain (Show British list).


We are grateful to Tom Murray for making his pictures of Myzocallis castaneae available for use under a creative commons licence.

For taxonomic details we have used the accounts of Fitch (1856) and Quednau & Remaudiere (1987) together with information from Roger Blackman & Victor Eastop in Aphids on Worlds Plants. We fully acknowledge these authors and those listed in the reference sections as the source for the (summarized) taxonomic information we have presented. Any errors in identification or information are ours alone, and we would be very grateful for any corrections. For assistance on the terms used for aphid morphology we suggest the figure provided by Blackman & Eastop (2006).

Useful weblinks


  • Essig, E.O. (1917). Aphididae of California. University of California Technical Bulletin 1(7), 301-346.

  • Fitch, Asa (1856). Third report on the noxious and other insects of the State of New York. Transactions of the New York State Agricultural Society 16, 315-490. Full text

  • Quednau, F.W. & Remaudière (1987). Révision des espèces du sous-genre Castaneomyzocallis subg. nov. du genre Myzocallis trouvées sur les chataignieres (Castanea) en Amérique du Nord (Homoptera: Aphididae). The Canadian Entomologist 119, 339-354. Abstract