752 



REPORT UNITED STATES GEOLOGICAL SURVEY. 



toward the middle of the wiug, tlie third tooth beiug at the eud of the baud. There 

 i8 a row of (lark dots along the outer edge of the stripe ; a row of blackish dots along 

 a pale shade just outside of the front edge of the wing, and two diverging rows of 

 blackish dots diverging upon the tip or apex of the wing. The fringe is marked with 

 a few dark spots. The middle of the wing next the white band is darker than the front 

 edge, wbile a,faint yellowish shade runs along the middle of theouter half of the wing 

 toward the tip, inclosing a few black dots. It expands a little over half an incb. 



Remedies. — Should young plants be attacked by the worms, the best 

 remedy would be to shower them with soap-suds. For the autumoal 

 brood of worms the plants should be pleutifully showered ; and if this is 

 not eificacious, the worms, and the cocoons especially, should be picked 

 off by hand. 



The Cabbage Plusia, Plusia brassic(e Riley. (Fig. 25.)— In August and September, 

 gnawing large, irregular holes in the leaves; a rather laige, pale-green caterpillar, 



marked with still paler, more opaque 

 lines, and with three pairs of abdomi- 

 nal feet, being a semilooper, and 

 changing to a grayish-brown moth, 

 whose wings are marked with a dis- 

 tinct silver interrogation mark. 



This caterpillar has been 

 found by Mr. Eiley to do con- 

 siderable mischief in Missouri. 

 I quote his account of its ap- 

 pearance and habits: 



"In the month of August 

 and September, the larvse may 

 be found quite abundant on 

 this plant, gnawing large, ir- 

 regular holes in the leaves. It 

 is a pale-green translucent 

 worm, marked longitudinally 

 Fig. 25.— Cabbage Plusia. a, caterpillar, 6, pupa with Still paler, more opaque 

 iu.tscoccon,c,moth. After Riley. y^^^^^ and, like all the known 



larvae of the family to which it belongs, it has but two pair of abdominal 

 prolegs, the two anterior segments, which are usually furnished with 

 such legs in ordinary caterpillars, not having the slightest trace of any. 

 Consequently, they have to loop the body in marching, as represented 

 in the figure, and are true 'span-worms.' Their bodies are very soft and 

 tender, and as they live exposed on the outside of the plants, and often 

 rest motionless, with the body arched, for hours at a time, they are espied 

 and devoured by many of their enemies, such as birds, toads, &c. They 

 are also subject to the attacks of at least two parasites, and die very 

 often from disease, especially in wet weather ; so that they are never 

 likely to increase quite as badly as the butterflies just now described. 



'' When full-grown, this worm weaves a very thin, loose, white cocoon, 

 sometimes between the leaves of the plant on which it fed, but more 

 often in some more sheltered situation, and changes to a chrysalis, 

 which varies from a pale yellowish green to brown, and has a consider- 

 able protuberance at the end of the wing and leg cases, caused by the 

 long proboscis of the inclosed moth being bent back at that point. 

 This chrysalis is soft, the skin being very thin, and it is furnished at 

 the extremity with an obtuse roughened projection which emits two con- 

 verging points, and several short, curled bristles, by the aid of which 

 it is enabled to cling to its cocoon. 



"The moth is of a dark smoky-gray, inclining to brown, variegated 

 with light grayish-brown, and marked in the middle of each front wing 



