CYCLOPIDES PAL^MON. 197 



and sylvius of Europe (Edwards). Ovum. — Egg laid in confinement ( ? s from 

 Nepigon, in the Lake Superior district), on Poa pratensis. Pale greenish-white,, 

 hemispherical, broader than high, apparently smooth, under magnification very 

 faintly and vertically grooved or wrinkled, and densely and uniformly pitted with 

 deep pores, which are wide at the mouth and taper to a fine point (Fletcher) ; in 

 their vertical parts, the wrinkles are about 0'06mm. apart ; surface densely and 

 uniformly punctate with very distinct, short, oval punctures, whose longer axis is 

 vertical and about '003nnn. in length, arranged to a certain extent in short, irregular, 

 sinuous series, giving a faint vermiculate effect. Diameter of egg, '86mm. ; approxi- 

 mate height, '48mm. ; puncta? about '008mm. in diameter (Scudder). Eggs laid 

 July 13th, hatched July 23rd. Larva. — First instar (newly-hatched): Length, 

 2'5mm. ; breadth of head, 0'45mm. ; of body, 0'35mm. ; length of bristles, O'OSinm. ; 

 head large, smooth, black ; thoracic shield narrow, black, bearing a few slender 

 hairs ; body yellowish-white, slender, of equal thickness throughout, bearing on 

 each side four series of trumpet-shaped bristles. Duration of stage five days. 

 Second instar: Length 3' 5mm. ; head white and furrowed at apex ; thoracic shield 

 black, much smaller than in first stage ; body pale green, with two narrow white 

 lines on each side, one subdorsal, the other supralateral ; spiracles yellowish ; 

 whole body covered with a short pubescence. Duration of stage, five days. 

 Third instar : Length 6'5mm. ; head rather higher than broad, slightly broadest 

 at the base ; rounded at apex, bilobed by reason of a deep frontal groove ; mandibles 

 and two clouds on cheeks fuscous ; thoracic shield transparent and hardly discern- 

 ible ; body pale green, translucent, the dorsal vessel and ramifications of trachea? 

 showing plainly through the transparent skin ; on either side a pale subdorsal band 

 with irregular edges, a distinct, clear, white supralateral stripe, and a very faint 

 snprastigmatal line. The subdorsal bands unite on the anterior fold in the anal 

 segment ; the supralateral stripes at the end of the anal flap. Duration of stage, 

 seven days. Fourth instar : Length 12'5mm. ; head lighter in colour, without 

 the fuscous marks on the cheeks, of the same width as the cylindrical body 

 (Fletcher) ; head pale greenish in colour with a bluish tinge, obscured with very faint 

 reddish-fuscous in a broad mottled stripe bordering the suture above the frontal 

 triangle, and in a similar belt passing down the middle of each hemisphere, from 

 the posterior point of the former, toward the ocelli, but fading out before reaching 

 it ; hairs white ; ocelli black ; mouth-parts pinkish at incisures and edges ; body 

 very pale yellow, nearly uniform ; the dorsal shield of first thoracic segment of the 

 colour of the head, with a median dusky line through it ; last abdominal segment 

 finely edged with fuscous and a little obscured above ; an exceedingly faint, slender, 

 greenish, dorsal stripe, and a slightly wider, but otherwise entirely similar, lateral 

 stripe the whole length of the body ; legs and prolegs concolorous ; their claws, and 

 the spiracle lips, pale testaceous ; papilla? concolorous, hairs pale brown ; length 

 8mm. ; breadth of head, l'25mm. (Scudder). Duration of stage, fifteen days (Fletcher). 

 Fifth (last) instar (newly moulted) : Length, 18'75mm. ; head greenish, tinged 

 with yellow ; a little larger than pro thorax and anal segment, but smaller than rest 

 of body ; squared at base ; rounded at apex : deeply grooved down front ; width at 

 base, about equal to height ; surface minutely roughened ; ocelli black, arranged in 

 semicircle, following contour of face, four in front and two on lower side, the third 

 and fourth twice the size of the others ; mandibles white with black tips ; labrum 

 black ; prothoracic shield not distinguishable ; body glaucous-green, with a pale 

 subdorsal band, clearly defined with white above, much paler below, leaving a 

 distinct green dorsal stripe ; supralateral stripe conspicuous, creamy- white and 

 clearly defined, not so wide as the pale subdorsal band ; below this and halfway to 

 the spiracles is a very pale, thread-like suprastigmatal line ; spiracles white, very 

 inconspicuous on a thread-like line (which may only be the trachea) showing 

 through the skin). On the meso- and metathorax, there appear to be 

 beneath the transparent skin, instead of spiracles, knots of trachea?. The 

 whole body, including the head, minutely shagreened and covered with small 

 piliferous papilla?, which on the pro-, meso- and metathorax are black at the base of 

 the hairs. The subsegmental divisions are — the prothorax transversely grooved, the 

 niesothorax three equal subsegments, the metathorax four small subsegments ; 

 abdominal segments 1-7 with five subsegments, the anterior twice the width of the 

 second, which, again, is twice the width of the other three ; the 8th abdominal, three 

 equal subsegments ; the 9th abdominal, two small folds ; the 10th consisting of the 

 anal flap. Last instar (at hybernating stage) : The shape of the mature larva 

 differs from that of the early instars, the body being largest in the middle and 



