114 PAPERS ON" CEEEAL AND FOEAGE INSECTS. 



Tlie gamma mark is somewhat differently shaped : Both its upper arms di- 

 verge, thus cutting off a broader equilateral triangle, through the upper 

 median border, between them. The outer arm of this figure forms at its inner 

 side an obtuse angle and is directed parallel with the hind edge (of the wing) 

 while in the European species it is more basally directed. The lower arm of 

 the gamma sign runs nearly horizontal. In this direction the black enclosed 

 part, supported by the two outer arms, is more snout-shaped while in the Ger- 

 man forms this form is approximately a rectangular space, rounded at its 

 apex. The ring spot is surrounded by a whitish margin, elongate, and inclined 

 very obliquely basally. The posterior diagonal band runs from the subcostal 

 to the inner branch of the median (branch 2), not in a smooth curve as in 

 gamma but in an unbroken straight line and is not so strongly curved basally 

 opposite the lower arm of the gamma sign as in the latter. On the under 

 surface, as in the French forms, the wings are clear white with, especially on 

 the forewings, sharp black mottlings. The remainder of the border of the 

 underside, as is also the color of the hind wings, is lighter colored than the 

 European forms. This form may be easily separated from moderately light 

 varieties in color and design by these important distinctions— the gamma sign 

 and the posterior diagonal band. 



Whether we have to do with a distinct species, a local variety, or merely 

 an accidental variety, must be proved by more extensive comparisons. 



Specimens of gamma from the Atlantic States, where they are said to be indig- 

 enous by Ruhordem, Koch, and Grote, I have not yet seen. They are, when 

 the calif arnica form is considered with them, spread over the whole northern 

 hemisphere from Greenland to Abyssinia. They should be found even in New 

 Holland [Australia], cf., my Geographical Distribution of the Butterflies of 

 Germany, etc., Volume II, page 219. 



PARASITES. 



This moth is severely parasitized. At the field laboratory in 

 Pullman, "Wash., we obtained five hymenopterous and two dipterous 

 parasites and observed a disease during the seasons of 1909 and 1910. 



On July 12, 1909. two small larvae of the alfalfa looper, measuring 

 about 11 mm. in length, had contracted to 8 mm., became turgid, quite 

 hard, and changed to a rich ferruginous brown. On July 22 of 

 the same year two specimens of Rhogas autographce Vier. (fig. 16) 

 emerged. On close examination of this improvised puparium it is 

 found to be almost entirely made up of the abdominal segments 7 to 12 

 of the lepidopterous larva (see fig. 47) . The thoracic and anterior ab- 

 dominal segments 1 to 6 contract to form an almost black annulated 

 cap oyer one end of the puparium, with the transparent head shield 

 terminating this cap. Segment 13, bearing the anal prolegs, termi- 

 nates the other end of the puparium and is also transparent. Seg- 

 ments 9 and 10 each bear the transparent skin of their respective 

 prolegs. The hair papilla? on segments 7 to 10 are pale and col- 

 lected in a darker elevated band around the middle of their respective 

 segments. The adult in emerging gnaws a smooth, circular hole 

 through the dorsum of the eleventh and twelfth segments. 



