1918.] Baii^i PeasiiAd : AndtOiiiij af a Chiionomid Laiva. t3 



the sides of the labium. Innnediatelj in front of the labium lies the 

 openin,ii: of the buccal cavity. Ventrally in the post-antennal region the 

 chitin is thickened to form the labium (lb) or the lower lip in the middle 

 and two striated flaps (/) on its two sides. The flaps bear a large number 

 of setae, and are brush-like structures which help in closing the mouth 

 opening on the sides. 



On the lateral sides of the head two pairs of pigment spots or simple 

 eyes (e) are present. The antemiie [an) lie in front of the eyes. Each 

 antenna consists of a large basal joint arising out of a cup-shaped 

 depression on the head. No sensory spot can be distinguished on the 

 basal joint of the antennae. To this basal joint two ramii are attached, 

 the outer one is five-jointed, and the inner is a long unjointed hair-like 

 structure. 



The mouth -parts consist of a pair of large mandibles {met.) and tw^o 

 pairs of maxillae. The mandibles (fig. 5) are large heavily chitinized 

 structures without any setae. They are attached by a broad base and 

 have a curved pointed tip ; their inner cutting margin bears a number of 

 teeth. The first pair of maxillae {mx. fig. 6) are two-jointed structures, 

 one on each side of the buccal opening and arising near the base of the 

 mandibles (fig. 4) ; the upper joint is small and setose. The second pair 

 of maxillae are fused to form the labium {lb. fig. 4) which forms the lower 

 margin of the funnel shaped buccal cavity. The labium has a toothed 

 anterior margin with the teeth pointing forwards. Above it lies another 

 thin plate. Miall and Hammond call the upper the mentum and the 

 lower the submentum. 



Thorax.' — In a young larva the first three segments following the head 

 are the pro-, meso-, and metathoracic {t 1, t 2, t 3, fig. 1). These three 

 segments are quite distinct, but in a fully grown adult larva the line 

 separating the mesothoracic from the metathoracic segment is not 

 seen, the two forming a single structure. The notch separating 

 the prothoracic from the mesothoracic segment, however, persists 

 (%2). 



The prothoracic segment has a pair of club-shaped feet {L /.) armed 

 with two types of hooks. Both types of hooks are simple without 

 serrations or teeth. One type (fig. 7) is curved like a scythe, whilst 

 the other (fig. 7a.) is nearly straight. The curved hooks are arranged 

 on the margins of the knob at the end of the foot, and the straight 

 ones are in the centre. Both types of hooks, especially the curved 

 ones, are of use to the animal in collecting and planting the colonies of 

 Epistylis on its tube. The other two thoracic segments do not have any 

 appendages. 



Abdomen. — The abdomen is formed of nine segments (1-9, fig. 1), all 

 of which are alike except the last one, which bears appendages and other 

 outgrowths. It has a pair of large anal feet {a.j. fig. 1) ; these like the 

 thoracic feet bear hooks. The hooks are arranged in concentric circles. 

 The outermost ones have a very broad base and a much bent upper 

 surface (fig. 8c), in the inner ones the curve is not so marked (figs. 8a, 6), 

 whilst the centre ones have a much less curved upper portion (fig. 8). 

 Besides the anal feet described above, this segment bears two bunches of 

 five setae each (fig. 1), arising from conical papillae on the dorsal 



