1014 ENTOMOLOGICAL SOCIETY. G!) 



are usually the largest spiracles on the bod}'. There is a pair of rudimentary spiracles 

 between the mesothorax and meta thorax (Fig. 1). The presence of these spiracles 

 is of interest, they are open spiracles in the nymphs of insects with an incomplete 

 metamorphosis so far as observed, rudimentary or wanting in the larvge of insects 

 with a complete metamorphosis, but large and prominent and open in many of 

 their adults. These rudimentary spiracles have been found in all the larvae 

 examined, they can be identified as minute brownish spots in line with the other 

 spiracles. The abdomen bears a pair of spiracles on segments one to eight. The 

 spiracles on the first abdominal segment may be as large as the spiracles located 

 on the prothorax or only half their size, they are usually larger than the spiracles 

 on segments two to seven. The spiracles on the eighth segment are usually larger 

 than those on segments one to seven, frequently twice as large and sometimes as 

 large as the spiracles on the prothorax. The spiracles are usually all of the same 

 color and frequently surrounded hy a triangular black or fuscous mark as in (Fig. 

 €, p) Cimhex. 



The thoracic legs (Figs. 1, and .27) are fleshy and robust at their proximal 

 ends, slender and pointed at their distal ends. The coxa or proximal segment con- 

 stitutes the largest part of the leg, not only in length but in width. In the Tenthre- 

 dinidae the coxa is divided longitudinally by a suture into two parts the edges of 

 the suture and the proximal part of the coxa are frequently of a different color 

 from the adjacent parts, so that the legs appear to be marked by a brownish or 

 fuscous Y. The trochanter is a short narrow ring in the Pamphiliidae, but is 

 hardly indicated in the Tenthredinidfe. The femora and tibiae are sub-equal in 

 lengtli to the trochanter in the Pamphiliidae, though smaller in diameter, but 

 in the Tenthredinidse the femur is considerable longer than the tibia and much 

 longer than the trochanter. The tarsus and claws of each leg are fused and but 

 little if any longer than the tibia. The claw is hooked at apex. Many of the 

 species which cling to the edge of the leaf with the thoracic legs, have their legs 

 black, except at the joints. 



Abdominal legs or prolegs (Fig. 27, pi) are present in the families Xyelidae 

 and Tenthredinidae. They are fleshy protuberances and differ from the prolegs of 

 lepidopterous larvae in that they lack the circlet of terminal hooks. In the Xye- 

 lidse the prolegs are small and there is a pair on each segment. The most of the 

 siih-families of Tenthredinidae have prolegs present on segments two to eight 

 and ten. In the Xeniatina^, Hoplocampina?, and Acordulevcerinae the prolegs a're 

 large and placed on segments two to seven and ten, while in the Hylotominae they 

 are placed on segments two to six and ten. In the Xematinae and Hoplocampinae 

 the prolegs are placed along the lateral part of the ventral aspect of the segments 

 while in the Acordulecerinae they are minute tubercles placed close together ad- 

 jacent to the meson. In Phhhatrophia, which is a leaf-miner, there is a pair of 

 protuberances on each thoracic segment between the thoracic legs in line with 

 the abdominal prolegs. In those groups where the prolegs are present, they differ 

 from lepidopterous larvae in that they always have a pair of prolegs on the second 

 abdominal segment. The prolegs are generally of the same color as the ground 

 color of the body; in some species there is a round, black spot, pad-like, on the 

 cephalic side of each proleg. In some black larva, as Pteronus ventralis, the pro- 

 legs are white. 



The prolegs of the tenth abdominal segment, the- anal prolegs, are usually 

 larger than the others, longer and broader, and comprise the greater part of the 

 tenth segment (Fig. 27). In the larvae of certain species of the genus Pachynem- 



