304 DAVENPOKT ACADEMY OF NATURAL SCIENCES. 



joined closely to the tibia and has a limited movement either inward or 

 outward. Tlie claw is comparatively large, sliglitly curved, considera- 

 bly swollen at its base, and appears to be movable. The upper pair of 

 digitules are the longest and are inserted on each side a sliort distance 

 from the extremity. The lower digitules are shorter and appear to be 

 inserted on each side of the swollen base of the claw. Both pairs ex- 

 tend slightly beyond the tip of the claw, and are quite flexible and mov- 

 able. All the hairs of the leg appear to be articulated at their bases 

 and movable. They probably act as organs of touch,— the digitules be- 

 ing without doubt tlie most sensitive. 



The second and third pair of legs are inserted near the fore margins 

 of the mesothorax and metathorax respectively. They are as near as 

 may be exactly similar to the anterior legs in all particulars. 



The sjnrades (tig. 2(5, sp.) are surrounded by kidney-shaped chitinous 

 pieces, (thickenings of the integument), with the emargination inwards, 

 and are four in number. The first pair are situated on the prothorax 

 just behind and outward from the bases of the anterior legs; the second 

 pair between the meso- and metathorax behind and outward from the 

 bases of the middle legs. Extending from each spiracle to the margin 

 is a shallow grove, whfch terminates in the spined emargination above 

 mentioned. 



The abdomen is composed of nine segments of which the first six are 

 similar in form, being each of them a little longer at the sides than in 

 the middle, and furnished with a single slender spine at each side. They 

 gradually decrease iu size posteriorly, and the excess of the length at 

 the sides over that at the center of each segment continues to increase 

 until in the seventh segment the disproportion is so great that it forms 

 two large lobes wliich almost completely surround the eighth segment. 

 There are about three slender spines on each lobr? of tlie seventh sejiment. 

 The eigkth segment is very small and entirely surrounded by the seventh. 

 It is prolonged upward and backward into two large conical projections 

 (an) from the extremity of each of which issues a long deciduous seta or 

 filament about as long as the entire insect. On the conical projections 

 are two or three slender spines. Remaining between the cones is a 

 small triangular piece beneath which is supposed to be the anus. The 

 ninth segment is usually kept withdrawn within the eighth and seventh 

 segments. When the young larvse are placed in water they are very apt 

 to project it and I have frequently watched them gradually project and 

 withdraw it. [They appear to loose this power when they ^row older.] 

 When projected it appears nearly triangular and is tepninated by six 

 long spines arranged in two flat groups cemented together by a 

 waxy secretion, thus forming what appears to be a pair of leaf-like or- 

 gans (fig. 25 ov). In fig. 25 the ninth segment is represented protruded to 

 nearly its whole length, but occasionally the "leaf-like organs" are 

 made to extend in a line at right angles to the length of the insect ; in 25c 

 it has been partially contracted and the " leaf-like organs" brought togeth- 

 er so that they appear as but one group ; in 2o(l it has been entirely with- 

 drawn, so that the spines appear to arise from within the seventh seg- 



