230 Journal of Agricultural Research voi. xvi, N0.9 



DISTRIBUTION 



p. calyptrata Zett., occurs in Europe as well as America, although 

 it appears to be exceedingly rare in the former. Stein (1906)* neg- 

 lects to list this species in his paper. Zetterstedt (1846)' mentions 

 its occurrence in Sweden, stating that one specimen was taken near 

 Lund by Mr. D. Dahlbom and a second at Vadstena by himself. Two 

 specimens were also taken at Altenburg, Germany. In America it is a 

 common species, especially in New York State, where the author has 

 found it widely distributed. Stein (1897)' mentions its occurence in 

 Washington, Minnesota, Illinois, Pennsylvania, and Massachusetts. 

 To these the writer adds New Jersey and New York, having taken the 

 the species at Ithaca, Binghamton, and Tarrytown, N. Y., and Orange, 

 N.J. 



HOST PLANTS 



P. calyptrata mines exclusively in the leaves of several species of 

 Rumex. Adults have been reared from R. ohtusifolius and R. crispus. 

 Both species of Rumex are equally susceptible to the attack of the 

 miner. R. acetosa is evidently a third host plant. Eggs of P. calyptrata 

 were found on this plant. They hatched and the young larvae entered 

 the leaf, but the writer did not succeed in rearing adults. A large num- 

 ber of adults of other species were reared from larvae mining the leaves 

 of garden beets (Beta vulgaris), spinach (Spinacia oleracea) and Swiss 

 chard {Beta vulgaris var. cicla), as well as many weeds, such as Chenopo- 

 dium album, Amaranthus retroflexus, and Atriplex pattila; but P. calyp- 

 trata was not obtained from any of these. 



A number of experiments were performed to induce the larvae of P. 

 calyptrata to mine in the leaves of other plants. Three eggs were care- 

 fully removed from a dock leaf and placed on a beet leaf. Two days 

 later the eggs hatched, but the larvae died without entering the leaf. 

 In a second experiment four second-stage larvae were dissected from R. 

 ohtusifolius and placed on Chenopodium album. The following day the 

 four larvae were found dead. In a third experiment two third-stage 

 larvae from R. crispus were placed on C. album. The following day one 

 larva had entered the leaf and formed a small blotch mine, but the next 

 day the larva died. These experiments seem to substantiate the fact 

 that P. calyptrata mines solely in Rumex spp. 



LIKE HISTORY AND HABITS 



Eggs. — The eggs are glossy white, and in the field are laid usually 

 in groups of three to five, occasionally in groups of six or seven, but 



'Stein, P. die mir bekannten europaischen pegomyia-arten. In Wiener Ent. Ztschr., Jahrg. 

 35, Heft 2/3/4, P- 47-107- i9o6- 



2 Zetterstedt, J. W. diptera scandinavl.*. v. s, p. 1775, 1846; v. 12, p. 4751, iSss- Lundae. 



* Stein, P. nordambrikaniscbb anthomyiden ... In Berlin. Ent. Ztschr., Bd. 42 (1897), Heft 3/4 

 p. 239-241, 286. 1898. 



