424 N. E. MCINDOO. 



insect emerges from the last pupal stage, and the lighter one 

 {Chi) represents the chitin formed after emerging into the imago 

 stage. 



As already stated, instead of the olfactory pores of the lady 

 beetle, Epilachna, having pits, the chitin over each pore in the 

 legs is elevated domelike above the surface of the leg. The 

 olfactory pores (Figs. 24 and 25) in the legs of the two blister 

 beetles, Epicauta marginata and Epicauta pennsylvanica, have 

 only indications of pits. Their pore apertures are therefore on 

 a level with the surface of the legs. The olfactory pores in the 

 legs of the potato beetle, Leptinotarsa lo-lineata, have shallow 

 pits (Fig. 26, P). All four just enumerated species have hypo- 

 dermal gland pores distributed over the entire body except the 

 wings. These pores are perhaps most abundant on the elytra, 

 but they were never seen on the peduncles of these appendages, 

 and it is quite probable that the secretion from their glands 

 never covers the olfactory pores found on the wings and on the 

 peduncles of the elytra. Judging from the gland pores, the 

 hypodermal glands in the legs of Epilachna are more highly 

 developed than are those of the other three species. The gland 

 pores (Figs, i, 2 and 28, PorWGl) on the legs of Epilachna lie 

 on all sides and even among the olfactory pores, but in the legs 

 of the other three species the gland pores never lie near the 

 olfactory pores. When examined under a low-power lens the 

 legs and elytra of Epilachna appear wet, and many small yellow 

 flakes may be seen on them. The wet appearance is certainly 

 due to the secretion from the hypodermal glands and the flakes 

 are the remains of the secretion after it becomes dry. Thus 

 in Epilachna there seems to be a direct correlation between the 

 olfactory pores and the gland pores. Since the pore apertures in 

 the legs lie above the surface of these appendages, the secretion 

 from the hypodermal glands runs away from the pore apertures 

 instead of into them. Such a device enables both sets of organs 

 to function normally without the one hindering the other. 



In the legs the sense cells always lie in a blood sinus (Figs. 16 

 and 17, BlSin) some distance from the muscles (Fig. 28, M). 

 The nerves {N) are easily seen and branches {NB) are given off 

 which run to the sense cells {SC). The neurilemma (Fig. 17, 



