U.S. D. A., B. E. Bul. 82, Part II. Issued November 30, 1909. 
SOME INSECTS INJURIOUS TO TRUCK CROPS. 
THE PARSNIP LEAF-MINER. 
(Acidia fratria Loew.) 
By F. H. Cuirrenpen, Sc. D. 
In Charge of Truck Crop and Stored Product Insect Investigations. 
INTRODUCTION. 
Since the year 1903 this species, hitherto considered rare, has 
made its appearance nearly every year in the District of Columbia 
in such considerable numbers that by July beds of parsnip are found 
so extensively infested by the maggot or larva that at least 25 per 
cent of the leaves are sometimes destroyed. The leaves show mines 
of varying sizes, from that of a dime to others covering the greater 
portion of a leaf. In 1906 and 1907 the species could not be found 
in the District of Columbia, but it returned in 1908. A more com- 
plete account than has hitherto been available of the insect is here- 
with presented. 
EARLY HISTORY. 
Our first knowledge of the existence of this species as an enemy 
to crop plants was published in 1895 in a short illustrated note by 
Mr. D. W. Coquillett.c At that time it was recorded as having 
attacked parsnip leaves at Cadet, Mo., in June, 1891. The leaves 
had been quite extensively mined, and three adults were reared June 
23, proving to be Trypeta fratria, as it was then known. 
In 1899, Mr. R. W. Doane published a note on this species,’ 
recording its rearing from Heracleum from Almota, Wash., and its 
occurrence at Pullman, Wash. He considered Thomson’s liogaster 
the same species, and stated also that our species may be identical 
with the European Acidia (Trypeta) heraclei L., or celery leaf-miner, 
said to be a destructive enemy of celery in England. 
DESCRIPTION. 
The fly—The mature fly in life is a beautiful object. Its body is 
pale yellow, as are also the legs; the abdomen is pale green, and the 
wings are beautifully ornamented with yellow alternating with 
white, forming the pattern shown in figure 1, a. Near the middle of 
the anterior margin of the wings there is a dusky, nearly black spot, 
a Insect Life, Vol. VII, p. 383. 
b Journ. New York Ent. Soc., Vol. VII, p. 178. 
