THE SPIKE-HORNED LEAF-MINER. 



DISTRIBUTION. 



This species has a wide range of distribution within the United 

 States (fig. 1). It is known to occur from Indiana and Ohio in the 

 North to southern Florida in the South, and from Massachusetts in 

 the East to Washington, California, and New Mexico in the West. 

 It is probably to be found wherever its food plants thrive. Outside 

 of the United States it has been collected from Porto Rico and 

 Mexico. 



The following localities and other data have been compiled from 

 pinned specimens of this species in the United States National Mu- 

 seum collection: Beverly, Mass., August, 1911 (Burgess) ; Las Vegas, 



Fig. 1. — Map showing records of distribution of the spike-horned leaf-miner (Cerodonta 

 dorsalis) in the United States. (Original.) 



N. Mex. (H. S. Barber) ; Ames, Iowa, June, 1877; Orizaba, N. Mex., 

 January (H. Osborn) ; Colorado; High Island, Md., May, 1898 

 (Currie) ; New York, July, 1898; Arroyo, Porto Kico, February, 

 1899 (Busck) ; District of Columbia; Claremont, Cal. (Baker); 

 Biscayne, Fla. (A. Slosson). 



INJURY TO PLANTS BY ADULTS PUNCTURING THE LEAVES. 



The punctures made by the females of this species in leaves of 

 plants on which they feed and oviposit (PI. II, fig. 3) resemble very 

 closely those made by females of Agromyza parvicornis Loew, with 

 the exception that they are frequently somewhat longer and a trifle 

 narrower. Some of the punctures are twice as long as others. The 

 punctures are not made solely as receptacles in which to deposit 

 eggs, but apparently primarily as a means of acquiring access to the 



