176 ECONOMIC ENTOMOLOGY 



Control. — Spray every week with arsenical solution; i lb. Paris 

 Green, 4 lb. whale-oil soap, 40 gal. water before heads form and with 

 hellebore or pyrethrum after; spray with salt-tobacco solution_(i lb., 

 I lb., 5 gal. water). 



Pieris napi Linn, is a native species, but not so abundant as P. 

 rapCB. Wings nearly all white. 



Alfalfa Caterpillar {Eurymus eurytheme Boisd.). — (Consult Bull. 

 124, U. S. Dept. Agr.) Common, and a serious pest of alfalfa in the 

 West. 



Adult. — Yellow with the outer margins of wings black, dotted with 

 white in the female. A black dot in the middle of the fore wings and a 

 pale yellow spot in the middle of the hind wings. Two or more broods, 

 March-April. 



Eggs. — Minute, ribbed and cross-lined, spindle-shaped; laid on the 

 new growth. 



Larva. — Dark green, with a faint white line on each side; i inch 

 long. Spiracles black and red. Strips the leaves leaving bare stalks. 



Pupa. — Yellowish-green, ^^ inch long, suspended, head up, by two 

 threads to the stalks of alfalfa, weeds and grasses. 



Parasites. — Tachinids — Phorocera and Forntina; also Apanteles, 

 Pteromalus and Tricho gramma. A bacterial disease. 



Control. — -Pasture infested fields or cut when larvae appear in 

 numbers; irrigate after cutting; disk in the fall; co-operation. 



NYMPHALIDiE 



This family includes a large number of common butterflies such as 

 the Fritillarias or Argynnids; the Angle- wings or Vanessids, including 

 the beautiful Red Admiral {Vanessa atalanta); the Painted Beauty 

 {Vanessa virginiensis); the Cosmopolitan Butterfly {Vanessa cardui); 

 the Mourning Cloak {Aglais antiopa); the Comma Butterflies {Poly- 

 gonia Jaunus, P. comma, the "Hop Merchant," P. progne and P. inter- 

 rogationis); the Purple Butterflies {Basilarchia arthemis, B. astyanax, 

 B. archippus). Of these the larvae of the Comma and the Red Admiral 

 feed on the hop. 



The "Hop Merchant Caterpillar" often called the "Spring Currant 

 Caterpillar," attacks currants, gooseberries, hop, elm, basswood, etc. 

 Generally two broods a year. They are brownish-yellow and marked 



