Sept., 1902.] The Larva of Molanna Cinerea. 149 



splinter or snag of wood, while the case of the latter, being made 

 entirely of sand, could hardly be discovered, even if moving about in 

 clear shallow water. This case consists of a slender tube with a wide 

 sheath extending beyond on all sides, but farthest at the anterior end. 

 It is therefore of a flat conical shape, rounded at both ends, with the 

 greatest diameter at the anterior opening of the tube. Its length is 

 20 mm., its width 10 mm. Professor Klapalek says that before 

 pupation the larva of Molanna angustata removes the forward part of 

 the sheath and that the sides are also often much narrower than in the 

 larval stage. Such a condition of the case was frequently observed in 

 Molanna cinerea, but was not invariable, and might at all events be 

 due, in part at least, to the natural wearing away of the case which 

 can no longer be repaired by the occupant. 



The larva is slender, with its head at an angle with the main axis 

 of the body. Its length is 12 mm., its width 2 mm. The head and 

 thorax are of a yellow color. The sutures of the head are bordered 

 with black, forming with the suture of the pronotum a large Y, the 

 arms of which join near the rear of the head. The antennae stand just 

 posterior to the bases of the mandibles. They consist of two joints — 

 a broad conical one at the base, and a second shorter one which is in 

 turn surmounted by a stout bristle of about its own length. The mouth 

 parts are well developed. The labrum is of elliptical form —the 

 forward edge almost straight. The mandibles are very strong, carry- 

 ing two and three teeth on the right and the left side respectively. 

 Along the outer edge of each mandible, stand two long bristles. The 

 gula is a trapezoid in shape, longer than broad. It is of a dark brown 

 color. The labium is thickly set with hairs at its base. The 

 maxillary palpi are of a conical shape and are closely applied to the 

 maxillae. Each palpus has four joints, only the last extending beyond 

 the maxillae. On the inner edge of the maxillce are three stout 

 bristles. The labium is conical in shape, carrying on each side of its 

 point a three-jointed palpus. At its very tip the opening of the sali- 

 vary (silk) glands may be seen. 



The thorax is of the same color as the head. The pronotum is more 

 heavily chitinized than the other divisions. Its anterior edge is gently 

 arched. The posterior edge forms two arches, the incision between 

 which is continued to form the longitudinal suture almost to the an- 

 terior edge. The entire posterior edge is margined with black. The 

 forward half of the mesonotum is covered with a chitinous shield which 



