2 BULLETIN 834, U. S. DEPARTMENT OF AGRICULTURE. 



HISTORY OF DISCOVERY OF THE INSECT IN AMERICA 



Specimens of a sawfly were collected by C. W. Johnson at River- 

 ton, N. J., some time prior to 1899, the exact date unknown. These 

 were submitted to Dr. W. H. Ashmead for determination and pro- 

 nounced by him a new species, to which he gave the manuscript name 

 of Calameuta johnsoni. Under this name, misspelled CaZamenta ]ohn- 

 soni, the record was published, without description, in the second edi- 

 tion of Insects of New Jersey, by John B. Smith (39). 1 A description 

 based on these specimens was later published by Ashmead (10) . Sub- 

 sequently the type specimens were examined by Dr. J. Chester Brad- 

 ley, who recognized in them the European species Tracheitis tab id us 

 Fabricius, and under this corrected name the record of the original 

 collection was again published in the third edition of Insects of New 

 Jersey (45). At that time, and for some time thereafter, nothing 

 was known of the food plants of the species in this country. Such 

 European records as existed were in the Russian literature, and be- 

 cause of difficult}' in translation were largely overlooked. Since 

 Trachelus tabidus was not known to be causing any injury, no par- 

 ticular attention was paid to it. 



During the summer of 1918 a complaint was received by the Bu- 

 reau of Entomology from a correspondent at Gaithersburg, Md., re- 

 garding the work of some insect which had caused his ripening wheat 

 to fall badly, and the writer was detailed by Mr. W. R. Walton, in 

 charge of Cereal and Forage Crop Insect Investigations, to investi- 

 gate the outbreak. 



Specimens of the injured stalks were received from the corre- 

 spondent, some of which proved to contain larvae of what was readily 

 determined as a species of Cephidae. The insect was at first thought 

 to be either Cephus pygmaeus Linnaeus or Cephus ductus Norton. 

 The former species had been known in the vicinity of Ithaca, N. Y., 

 many years before, but so far as the records indicated, had succeeded 

 in spreading but little from the point of original infestation and had 

 never been recorded as seriously injurious. Cephus ductus was 

 known only from the western United States and was not believed to 

 occur east of the Mississippi River except for a few localities in 

 Michigan. 



When the Maryland infestation was brought to the attention of 

 Mr. S. A. Rohwer, specialist on sawflies, of the United States Depart- 

 ment of Agriculture, Bureau of Entomology, he at once suggested 

 the possibility that the insect might be Trachelus tabidus Fabricius. 

 Several adult specimens of this species in addition to those originally 

 taken at Riverton, N. J., were in the United States National Museum. 

 These, as shown by the labeling, were collected at two or three differ- 



Numbers in parenthesis refer to " Literature cited," p. 14. 



