E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Euphilotes battoides Mattoni, [1978]
Square-Spotted Blue
Family: Lycaenidae (Gossamer Wings)
Species account authors: Crispin Guppy and Jon Shepard.
Extracted from Butterflies of British Columbia
The Families of Lepidoptera of BC
Introduction to the Butterflies of BC
Photo of species

© Norbert Kondla  Email the photographer   (Photo ID #74038)

E-Fauna BC Static Map
Distribution of Euphilotes battoides in British Columbia
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Species Information

Click on the image(s) below to view an expanded illustration for this taxon.

Illustration Source: Butterflies of British Columbia by Crispin Guppy and Jon Shepard © Royal BC Museum


The Square-spotted Blue has a wide postmedian orange line on the ventral hindwing. There is no adjacent area of distal submarginal metallic scales as in the Acmon Blue. The uppersides of the male wings are blue with black borders. The uppersides of the female wings have a rich brown ground colour, with the ventral postmedian orange area repeated. The female dorsal forewing has no orange. The valve of the male genitalia is shown in the figure.

Immature Stages

Comstock and Dammers (1934) first described the immatures. The egg is bluish white. The mature larva is extremely variable in colour, from pale blue green through various yellow/green shades to a uniform pink. In the more common green form, there is a dorsal chocolate brown line and, laterally on each side, an elongated chocolate brown triangle with the longest tip pointed caudally. The mature larva is 11 mm long. The larval head is black and the spiracles dirty white. The pupa is 5-7 mm long and pale chestnut in colour, with dark chocolate stigmata. There are no hairs on the surface and there is no silken attachment.


BC populations are the Great Basin subspecies, E.b. glaucon (W.H. Edwards, 1871) (TL: Storey Co., NV).

Genus Description

The name Euphilotes is derived from the Greek prefix eu (true) and Philotes, the genus in which the butterflies were previously placed.

In this genus and the next, the eyes are smooth or with only a few hairs. Veins 7 and 8 of the forewing are joined at base. There are also genitalic differences. Euphilotes species are much smaller than Glaucopsyche, and feed on the plant genus Eriogonum. There are four Nearctic species in the genus Euphilotes.

Currently only one species is recorded for BC, E. battoides. A second species, E. enoptes (Boisduval, 1852), occurs very close to the BC border, in Okanogan County, WA. It is not possible to tell the two species apart by wing characters in our area. The critical part of the male genitalia is therefore shown in the figure to help identify the two species. There is also the remote possibility that a third species, E. ancilla (Barnes & McDunnough, 1918) with male genitalia identical to those of E. enoptes will be found in extreme southeastern BC.


Adults of the Square-spotted Blue fly from mid-May to early July, and into late July at the highest elevations. Eggs are laid singly on flowers of Eriogonum spp., the larval foodplant. Larvae feed only on the flowers, and pupation occurs in the drying flower heads, which remain on upright stems until the following summer. The Square-spotted Blue overwinters in the pupal stage and emerges as an adult the following spring. Emergence appears to be tied to the flower development of the foodplant, and not the first warm weather in spring.


The Square-spotted Blue is found in the Southern Interior and the southwestern West Kootenay at most localities where the larval foodplant occurs, including isolated populations on high (1,500-2,200 m), exposed ridges.



The Square-spotted Blue ranges from the Southern Interior of BC south to Baja California and NM.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
NativeS4S5YellowNot Listed
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Additional Photo Sources

General References

Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2024-05-21 11:24:33 PM]
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