6346 



Insects. 



it ; then they loved to feed on that part of the stem which is just above 

 the root, but they also ate down into the root itself, and appeared only 

 exceptionally to feed on the leaves. 



About the middle of September we took out the caterpillars pro- 

 duced on the grasses brought from Iceland ; at that time they were all 

 (about fifty) 5 to 8 mills, in length. At the end of November I again 

 examined them, and found, to my great astonishment, that about five 

 were already nearly as large as the largest specimens found in Iceland, 

 the perfect identity of which with our exulis reared from the eggs was 

 now as clear as day. About nine were half grown, and of the re- 

 maining six or eight still living ones, some were scarcely larger than 

 they were in September. These facts, taken in connection with those 

 observed in Iceland, are sufficient proof that our exulis sometimes 

 passes one, two or even three winters in the larva state. 



The young larva, when it comes out of the egg measures 2*5 to 

 3 mills, in length. With the exception of the darker head and lighter 

 anterior feet, the colour, position of the spots and habit, are exactly 

 like those of the full-grown larva. The first pair of prolegs are not 

 very much shorter than the hinder ones. The position of the little 

 hooks on the prolegs in the semicircle on the inner side of the lower 

 plate is just the same in the adult larva, except that the number of 

 the little hooks, now eight to ten, is then twelve to fourteen. The 

 full-grown larva is 42 to 46 mills, long. It has no resemblance what- 

 ever to any larva of Hadena or Polia that I know. The hinder seg- 

 ments gradually but perceptibly diminish in breadth after the seventh 

 or eighth. The colour is dirty white with a shade of gray, the head 

 chestnut-brown, the plate of the thoracic and anal segments and the 

 anterior feet yellowish. The labrum and eye-marks are rather dark, 

 and just where the hemispheres join are two dark spot-like depressions. 

 The head is scarcely half as broad as the following segment, which, 

 on the upper side, is entirely overlaid by the exceedingly strong tho- 

 racic plate. The second and third segments bear on the upper side 

 several very obscure dark spots, which are scarcely distinguishable 

 from the ground-colour. The position of the spots appears to agree 

 with other Noctua larvse. The slightly raised spots always bear a 

 rather long reddish hair springing from a dark speck. The thirteen 

 segments of the larva, as shown in my " Dissertatio de Sesiis agri 

 Berol." are here very distinctly seen. The rudimentary stigmata are 

 always very distinct on the twelfth segment, and mostly appear close 

 under the fore part of the anal plate. The anal plate itself is very 

 strong, in form a somewhat elongated semicircle, and bears as usual 

 eight hairs. 



