On Certain Grass-Eating Insects. 73 



Egg. — Creamy white in color when first laid, quickly changing to a scarlet 

 and then to an intense geranium red ; just before hatching the blackish head 

 of the embryo shows through the thin shell ver}' distinctly. Form nearly 

 oval ; size .51 mm. by .39 mm. The egg-shell is quite fragile and frequently 

 collapses when the larva leaves it. There are twenty-two longitudinal ridges 

 and numerous smaller transverse ridges. The circular markings around the 

 micropyle are very characteristic PI. XII., Fig. 11. 



Larva, first stage. — Head diameter .21 mm.; body diameter .i8 mm.; 

 length I. mm. Head a brownish black, clypeus yellowish, antenna? nearly 

 colorless, scattered hairs occur on the head ; thoracic shield brown with a 

 reddish tinge from the body contents ; body a variable red, the color being 

 the most intense in the thoracic region ; there is a light stigmatal line ; 

 tubercles blackish and bearing dark hairs ; prolegs almost rudimentary. 



When about a month old the larvae are 1.5 cm. long; the head is yellowish 

 with irregular black markings ; the body is brown with large blackish tuber- 

 cles. When about six weeks old the larvae are 3 cm. long and quite stout ; 

 the color has not changed. 



14. The Yellow Striped Crambus. 



Crambus giradellus. 



plates II., VIII., XIII., Fig. 14. 



This mofh is one of the largest Crambids. The adults may be 

 recognized by the rather broad yellow stripe extending through 

 the middle of a nearly pure white fore wing. This insect is con- 

 fined to high land and is usually found in open fields. The moths 

 fly in the afternoon and during the early evening. Light seems 

 to have little attraction for them ; in 1889 only four adults were 

 taken in the trap-lanterns. The species is not very abundant, 

 though widely distributed. The moths fly the latter part of June 

 and more or less during July. Oviposition covers a period of 

 from several days to a week ; most of the eggsbeing laid during 

 the first few days. Observation of other species shows that the 

 average female probably lays about four hundred eggs ; one female 

 laid two hundred and twenty-five eggs in four days; .she had 

 doubtless laid some before being captured. The eggs hatch in 

 about ten days. The larvae feed upon grass and construct the 

 typical Crambid nest. (Fig. 7). 



£-^^._Creamy white when first laid, gradually changing to a bright 

 orange color before hatching. Form elliptical oval; size .51 mm. by .33 

 mm. The egg-shell has seventeen longitudinal ridges and numerous smaller 

 transverse ridges. 



