PSYCHE 
Vol. 59 December, 1952 No. 4 
THE BIOLOGY OF NEARCTIC LEPIDOPTERA. 
II. FOODPLANT AND PUPA OF HE MI ARGUS I SOLUS 
By Charles L. Remington 
Osborn Zoological Laboratory, Yale University 
In early July 1943, about 10 mi. S. of Abilene, Taylor 
Co., Texas, I discovered a lycaenid larva feeding on a large 
pod of mesquite, Prosopis juliflora (Swartz) DC. It was 
confined and fed, and on 18 July it pupated. The imago 
emerged on 25 July and proved to be Hemiargus ( Echinar - 
gits) isolus (Reak.). This was of considerable interest, 
since the life-history and foodplants of this very common 
Blue were wholly unknown. During August and Septem- 
ber H. isolus was abundant in Prosopis groves, but no more 
larvae were found. While Prosopis may be the primary 
foodplant in the Southwest wherever it occurs, it obviously 
is not the only plant ; H. isolus ranges far beyond the limits 
of Prosopis in the West and even appears to have endemic 
colonies east of the Mississippi (Remington, 1942). Other 
species of Hemiargus have been recorded feeding on Pro- 
sopis , Mimosa , Macroptilium, Chamaecrista, Abrus, Pith- 
ecolobium, Guilandina, Astragalus , and Medicago. The food- 
plant record for H. isolus in Riots’ new book (1951, p. 159) 
is based on a verbal communication from the writer. 
This being the first record of early stages of H. isolus , a 
brief description, prepared from the pupal shell, is given as 
follows : length 6.2 mm. ; length of dorsum of abdomen 
(ignoring curvature) 4.0 mm.; width of abdomen just 
caudad of wing cases 1.9 mm.; length of maxillary sheath 
2.2. mm. (extending 1.0 mm. beyond tip of sheath of pro- 
thoracic legs and 0.3 mm. beyond sheath of mesothoracic 
legs and exceeded by wing cases and antennae by 4.0 mm.) ; 
hairs very sparse, especially on dorsum, but of highly dis- 
tinctive shape — columnar and very rough in outline, not 
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