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Montana Field Guide

Montana Field Guides

Square-spotted Blue - Euphilotes battoides

Native Species

Global Rank: G5
State Rank: SNR

Agency Status

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General Description
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 1.1-1.3 cm. Forewing fringe white with black checkers. Uppersurface of males blue with black outer margin with or without trace of orange aurora on hindwing outer margin, females brown often with orange aurora on hindwing outer margin. Undersurface gray-white with black spotting heavy and squarish (more so on forewing), hindwing orange submarginal band usually of bold and fused spots, lacking distal submarginal metallic scales.

One flight; June to July for the glaucon subspecies (Scott 1986). Late May to early August for the glaucon subspecies (Glassberg 2001). July to September in the Rocky Mountain states (Ferris and Brown 1981), late March to early August in Oregon and Washington (Pyle 2002), mid-June to early August in Oregon (Warren 2005), mid-May to late July in British Columbia (Guppy and Shepard 2001).

Diagnostic Characteristics
Difficult to distinguish in field from Euphilotes ancilla based on external characters; data on flight date, exact locality, larval hostplant very useful, and determination may ultimately require genitalia dissection (Glassberg 2001; Guppy and Shepard 2001). Helpful characteristics include presence of the submarginal orange aurora on both surfaces of the hindwing, on the undersurface the orange aurora usually bold with fused spots and lacking distal submarginal metallic scales; wing fringes white and checkered, undersurface suffused basally with gray, forewing undersurface with prominent black spots squarish, somewhat larger than on forewing.

Species Range
Montana Range Range Descriptions


Range Comments
Southern British Columbia south to southern California, east to western Montana, southwestern Idaho, southwestern Colorado, western new Mexico (Opler and Wright 1999); 1524 m to 2896 m elevation in Colorado (Brown 1957; Scott and Scott 1978), 1830 m to 2592 m elevation elsewhere in the Rocky Mountain states (Ferris and Brown 1981), 914 m to 2134 m elevation in Oregon (Warren 2005), 1500 m to 2200 m elevation in British Columbia (Guppy and Shepard 2001). In Montana, reported from six counties (Beaverhead, Jefferson, Lincoln, Madison, Missoula, Ravalli) in the western 1/5 of the state (Kohler 1980; Stanford and Opler 1993; FLMNH Lepidopterists' Society database; Butterflies and Moths of North America database). Uncommon to locally common in the Pacific Northwest for the glaucon subspecies (Glassberg 2001).

Observations in Montana Natural Heritage Program Database
Number of Observations: 1

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)


Open habitats such as coastal dunes, sagebrush-steppe, desert canyons, open woodland, dry slopes and hillsides, exposed ridges, above treeline in alpine terrain (Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002). Habitat in Montana not described, but probably similar.

Food Habits
Larval food plants include at several species of Eriogonum (Scott 1986, 1992, 2006; Matonni 1988; Pyle 2002; Warren 2005), at least five of which (E. flavum, heracloides, ovalifolium, sphaerocephalum, umbellatum) are larval food plants for Euphilotes battoides glaucon, the subspecies which occurs in Montana. Adults feed on flower nectar (especially Eriogonum), dung, and mud (Scott 2014).

Reproductive Characteristics
Females lay eggs singly on host plant flowers (Scott 1986, 1992, 2006). Eggs hatch in about 5 days, reach L4 instar and pupate in about 30 days after oviposition. Larvae solitary, feed on flowers and fruits, build no nests, overwinters in litter or soil as pupae (Scott 1979, 1986; James and Nunnallee 2011). Larvae-ant association apparently not yet reported but likely, as has been documented for other species of Euphilotes (Ballmer and Pratt 1991). Males patrol throughout the day near host plants in search of females (Scott 1975b, 1986).

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Citation for data on this website:
Square-spotted Blue — Euphilotes battoides.  Montana Field Guide.  .  Retrieved on , from