Insects. 9745 



Life-History of Chorlobius Davus. — The egg is barrel-shaped, the sides convex, 

 and delieaiely ribbed, the extremities truncate, attached by the lower extremity to the 

 linear seliform leaves of Rliynchospora alba (beak-rush), on which ihey are laid at the 

 end of June, always singly, aud generally only one on a leaf, but sometimes two, and 

 very rarely three. The young larvae emerge in fifteen days, and crawling to the 

 extremity begin feeding; they feed during the day, and grow very slowly; 

 they rest on the leaves in a perfectly straight position, but on being annoyed fall 

 from iheir food on the Sphagnum or other mosses among which the Rhynchospora 

 usually grows, and there lie in a bent posture, as if dead, until all appearance of 

 danger has passed, when ihey reascend the leaves: when among the moss it is almost 

 impossible to detect them. At the end of August those under my care ceased to eat, 

 and on the Ist of September I made the following description: — Head semiglobose, 

 wider than ihe budy, slightly notched on the crown, beset with minute hairs; body 

 linear, its sides almost parallel, but slightly and gradually attenuated towards the anal 

 extremity, which terminates in two points directed backwards; dorsal surface trans- 

 versely and regularly wrinkled, and covered with extremely minute warts, which under 

 a lens give the surface the appearance of extremely fine shagreen; the dorsal wrinkles 

 divide each segment into sections. C»lour of the head dingy semitniusparent greeu; 

 the ocelli very prominent aud intensely black : colour of the body dingy green, with 

 five narrow, equidistant, distinct, purple-brown stripes; the interspace between the 

 second and third stripe on each side is intersected by a very narrow and indistinct 

 stripe, almost similar in colour to the other five, and the exterior purple stripe on 

 each side is bordered below by a pale glaucous, almost white stripe, extending 

 throughout its. entire length. Immediately after this description was written 

 the larvae disappeared, probably secreting themselves at the roots of their food- 

 plant. In the spring of 1865 I saw nothing more of these larvae, but received 

 a fresh supply on the 26tli of May, when they appeared full-fed. The larra then 

 rests in a perfectly straight position on the blades of the beak-rush, falls oflF 

 its food-plant when annoyed, and remains quiescent for some time as if dead, in a 

 somewhat bent position. At this date I made a second description: — Head rather 

 wider than the 2nd segment, distinctly exserted, prone, scabrous with minute warls ; 

 body cylindrical, slightly and very gradually attenuated towards the anal extremity, 

 which terminates in two parallel points above the anal flap, and direuted backwards; 

 surface of the body almost smooth ; warls indeed are observable, but so minute as not 

 to communicate a scabrous appearance, nor are there any noticeable hairs or bristles. 

 Colour of head and body a|)ple-green, inclining to olive-green ; head dull opaque, 

 uniformly coloured ; bo'iy striped ; a narrow mediodorsal stripe dark purple-green, 

 bordered on each side by a still narrower yellow stripe ; these three stripes terminate 

 before the anal point; on each side are two pale yellow stripes, one above the other 

 below the pale brown spiracles; the upper of these is bordered above and below with 

 dark bluish green, aud terminates in the anal flap, which is tinged with pink; the 

 lower terminates before the anal flap; ventral surface, legs and claspers boltle-green. 

 Two days subsequently— namely, on the 28th of May— they underwent pupation. The 

 pupa has the head truncate and slightly produced at the angles and also in the 

 middle; the wing-cases very slightly produced at the shoulders; the thorax is dor- 

 sally convex, with a very slight median keel; the pupa is suspended by minute 

 cremastrae from a white silken web spun on the edge of a leaf of its food-plant; the 

 colour of the wing-cases is pale brown, with a darker arcuate median linear mark 



VOL. XXIII. 3 A 



