PROCEEDINGS OF THE 



ENTOMOLOGICAL SOCIETY OF WASHINGTON 



VOL. 24 JANUARY 1922 No. 1 



LIFE HISTORY OF ETHMIA MACELHOSIELLA BUSCK. (LEP.) 



Bv AUGUST BUSCK AND CARL HEINRICH. 



Ethmia macelhosiella was described in 1907 (Proc. Ent. Soc. 

 Wash., vol. 8, p. 93) from a single male specimen collected late 

 in September, 1904, near St. Louis, Mo., by Mr. H. A. McElhose. 

 The species was considered rare and remained unknown except 

 for this unique type in the National Museum until the fall of 

 1916. On November 8, 1916, Mr. E. A. Schwarz brought from 

 Plummers Island, Maryland, a vial containing half a dozen 

 moths with the remark: "What is that common thing? There 

 are a hundred thousand millions of them on the island." The 

 moths were our rare Ethmia. The authors went the same day 

 to the island and found the striking black and white moth 

 abundant everywhere on the tree trunks as reported. Plum- 

 mers Island had probably been explored entomologically more 

 than any other American locality and the reason of our missing 

 this conspicuous species during all these years is partly explained 

 by the fact that it is not equally abundant every year, but more 

 so by the unusually late appearance of the moths, at a season 

 when the collecting of Lepidoptera is normally abandoned. 

 There was no clue to be discovered at that time of the year as 

 to its food plant and it was not before early last spring that we 

 gained further knowledge of the species. 



On May 5th last year (1920) Mr. Herbert Barber brought in 

 a small, prettily striped caterpillar found on a tree trunk at 

 Plummers Island. 



An examination of the setal arrangement proved the cater- 

 pillar to be an Ethmia. The authors immediately accompanied 

 Mr. Barber to the island in search of more material. Such 

 we found quite abundant on or near tree trunks. Apparently 

 the caterpillars were full grown and in search of suitable 

 quarters for pupation. Diligent search of the plants growing 

 in the immediate neighborhood was for a long time without 

 result and about to be abandoned when Barber discovered one 

 of the larvae on the leaf of a Phacelia. Renewed search on this 

 plant on a lower and more shaded, undisturbed part of the 

 island soon resulted in additional specimens. The brightly 

 striped larvae are quite conspicuous and feed exposed in full 



