INSECTS ATTACKINC WEEDS IN MINNESOTA. 139 



LAMFVS QUARTERS (Chcnot^odiinii album Lj Insects. 



The Spinach Leaf Miner (Pci^omyia liynsryaiiii Pan/J. 



This species is a pest of spinach, and otlier Chenoi)ocliaceae, 

 such as lamb's quarters. It is also recorded as breeding in Amar- 

 aiithus rctroflcxns, altho I have been unable to tind them here. The 

 species until recently has been known as P. vicinia, but Cory and 

 Knab have shown it to be a synonym of P. Iiyoscyatni, an European 

 species (Jour. Econ. Ent., June, 1916). in this paper, a detailed 

 account is given of the insect. In Minnesota, the larvae were first 

 observed the latter part of May and early June, while one adult 

 was reared on June 28. There are probably three broods during 

 the season. The egg is nearly one mm. long by 3/10 mm. wide. 

 It is whitish in color with one end rounded and the opposite end 

 truncate. Surface with a polygonal reticulation. The eggs are 

 deposited on the under surface of the leaf, generally three or four 

 in a row. 



Gnoriiiioscliciiia artiiiiisieUa Kearfott. 



I have called this species the wormweed web v/orm, having 

 reared it first from Artimesia. I have also found it mining in sun- 

 flower leaves and tying the terminal leaves of C. album. The small 

 larvae about ^ inch long were observed in June, l^ipation occurred 

 on July 7 and one adult emerged on July 14. 



PURSLANE (Portulaca olenwca L.) Insects. 

 The Purslane Saw Fly ( A[>rosihciia .oabriskci \\'ebster and Mally.) 



This very interesting little leaf miner occurs wherever purslane 

 is found. The full-grown larvae are nearly }/> inch long, greenish, 

 and make large blotch mines. Adults may be found flying about 

 the plants from June to September. The eggs are deposited in the 

 edges of the leaves, causing small lilisters which appear slightly 

 elevated and somewhat lighter than the surrounding tissue. These 

 swellings measure about 4 '5 mm. long by 3/5 mm. wide. There 

 appear to be several generations, for it takes only from seven to ten 

 days for the larvae to transform. The adults are black, about % 

 inch long, the male having forked antennae. Being abundant all 

 summer, this species could be used to advantage for study and 

 breeding purposes in schools. 



The natural enemies reared were one larval parasite ( Ichneu- 

 fidca sccnnda) and two egg parasites. The former is yellowish 



