Vol. 5, p. 97-100. July 2, 1924. 



Occasional Papers 



OF THE 



Boston Society of Natural History. 



A REVIEW OF THE NEW ENGLAND SPECIES OF 

 CHRYSOTOXUM. 



BY CHARLES W. JOHNSON. 



In 1907 at the Museum of Comparative Zoology I saw Loew's 

 types of Chrysotoxum which were in one of the small glass- 

 covered boxes in which the collection was shipped. This box has 

 since been misplaced. I made notes on the species at the time. 

 These were pubHshed in Psyche (vol. 14, p. 77-79, 1907) and 

 specimens compared with the types are in my collection. In the 

 Canadian Entomologist (vol. 56, p. 34-40, 1924), Mr. C. Howard 

 Curran has published a ''Synopsis of the genus Chrysotoxum 

 with notes and descriptions of new species." The determinations 

 in that paper are so much at variance with my notes and homo- 

 types, that I cannot refrain from reviewing the subject. My 

 remarks, with one exception, are confined to our eastern species, 

 as material from the West is limited. 



Chrysotoxum ventricosum Loew. 



In my note on this species I state, "The two types are marked 

 ' W. T.' [Washington Territory], and the original description gives 

 'Washington.' Osten Sacken's Catalogue gives 'Distr. Colum- 

 bia,' as does Williston in his Synopsis of the Syrphidae." It is 

 this error in habitat that has misled authors. Loew's note, that 

 this species is similar to Chrysotoxum arcuatum Linne except that 

 the base of the abdomen has black pile, seems to confirm my 

 statement, for my homotype from Colorado agrees with Chryso- 

 toxum arcuatum in my collection except for the black pile men- 

 tioned. The scutellum of the types shows faintly the dark 

 translucent disk so characteristic of the genus and cannot be said 

 to be "totum flavum." The short antennal joints and globose 

 abdomen readily separate it from the eastern forms that have 

 been inadvertently referred to it. I have seen no specimens of 

 Chrysotoxum ventricosum east of Colorado. 



Chrysotoxum derivatum Walker. 



This and the preceding species have served as a dumping-place 

 for doubtful species. There are only three items in Walker's 

 description of any real value for identification: "Scutcheon 



97 



