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SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 52 



The olfactory pores on several males and females of the Mexican 

 bean beetle were examined, but they were actually counted on only 

 one female, and these are illustrated in figures 6, 8, 9, 14, and 15. In 

 this study only one totally new fact was learned. In all the previous 

 studies on beetles, no olfactory pores were seen on the ventral side of 

 the peduncles of the elytra, but in this position on the bean beetle 7 

 pores were seen on one elytron and 6 pores on the other. The groups 



Fig. 14.^ — External view of chemoreceptors of adult Mexican bean beetle. A, 

 noninnervated hairs and group 5 of olfactory pores on trochanter of front leg, 

 X 500. B, ventral surface of distal end of maxillary palpus, showing numerous 

 noninnervated hairs (Hr) with their gland pores, isolated olfactory pores (P), 

 group 7 of olfactory pores (7), and a plate bearing numerous so-called taste 

 hairs (THr), X 100. C, group 7 of olfactory pores, markings on chitin, hairs, 

 and gland pores, X 5oo. 



of pores are numbered, as usual, from i to 7, and small letters are 

 used to indicate the position of some of the isolated pores. Group i 

 on the elytra (fig. 8, A) contains 58 pores on the left peduncle and 

 65 on the right one. Groups 2, 3, and 4 on the dorsal surface of the 

 wings (C) have as follows: Group 2, 58 and 64 pores; group 3, 43 

 and 38 pores ; and group 4, 70 and 64 pores. Isolated pores on the 

 wings are as follows : At a, 2 on the ventral side ; at h,S on the dorsal 

 side ; at c, I on the dorsal side ; and at d, 12 on the dorsal side and 8 

 on the ventral side. The number of pores in groups 5 and 6 and at e 



