REPORT OF THE STATE ENTOMOLOGIST I905 



69 



Upon them the common name of close-wings. A series of trap lan- 

 terns were run at Cornell University in 1889 and the material 

 therefrom shows that different species of Crambids fly from the 

 latter part of May throughout October, the greater number being 

 abroad in July, fewer in June and August and only one or two 

 species in May and September. This variation in the period of 

 flight probably indicates a corresponding difference between the 

 time the caterpillars of the several species attain maturity. This 

 is of considerable importance because most caterpillars feed much 

 more heartily just as they are completing growth, and were this 

 destructive period in the various species distributed over a series 

 of weeks the caterpillars would obtain a maximum amount of food 

 with a minimum injury to the grass. This is very probably what 

 occurs in nature. 



The life history of these forms, so far as known, may be sum- 

 marized briefly as follows : The adults fly as 

 described above and drop their pearly white 

 or yellowish, strongly ribbed eggs at ran- 

 dom in the grass, caterpillars hatching 

 therefrom in about a week. The young 

 larvae obtain shelter at the base of grass 

 stalks and at first eat only the underside of 

 the leaf, leaving the upper epidermis. They 

 soon construct a cylindric, web-lined retreat 

 to which they retire during the day. As 

 they attain a little size, portions of the leaf 

 are eaten away and soon the young cater- 

 pillar is strong enough to cut off a blade of 

 grass, drag it to its nest and even end it up 

 and draw the end down into its web-lined 

 shelter. This is evidently a provision so 

 that the little creature can feed during the 

 day without exposing itself to attacks from 

 various natural enemies. The partly grown webworms pass the 

 winter in their web-Hncd retreats and in the spring renew their feed- 

 ing, those of the vagabond Crambus, C. v u 1 g i v a g c 1 1 u s Clem., 

 completing their growth the latter part of May or early in June, at 

 which time the cocoon is spun. The caterpillars, however, remain 

 unchanged in their shelters for about two months or through Jtnie 

 and July, and the moths appear in the case of this s[)ocics during the 

 latter part of August and may be observed throughout September. 



Fig. I Crambus trjsectus, 

 tube of older larva at base of 

 grass stem, enlarged (Redrawn 

 from author's illustration) 



