THE OLFACTORY SENSE OF ORTHOPTERA 413 



belonging to twenty genera and representing the six families, 

 have been examined. Since the pores on only one specimen for 

 each sex in a species were counted, the total number of pores 

 recorded cannot be a fair average. 



a. Pores on head. Pores were found on all the head capsules 

 examined, except on four locustids (table 1, nos. 37, 38, 41, and 

 42) and on the five crickets examined (nos. 43 to 47). The num- 

 ber varies from to 40; the highest number being found in the 

 American roach (no. 6). 



The number of pores on the antennae vary from 16 (no. 24) 

 to 124 (nos. 33 and 34). Pores are always present on the second 

 antennal segments, and the numbers found on the first antennal 

 segments are as follows: no. 1, 9; no. 2, 14; no. 3, 8; no. 4, 15; no. 

 5, 4; no. 6, 24; no. 7, 17; no. 8, 4; no. 9, 1; no. 16, 2; no. 17, 1; 

 no. 18 (figs. 1 and 2), 8; no. 43, 2; no. 44, 4, and none on all the 

 others. No pores were observed on the remaining antennal 

 segments. 



Relative to various portions of the mouth-parts of the adult 

 specimens, the number of pores varies as follows: mandibles 8 

 (no. 9) to 110 (no. 2); maxillary palpi (nos. 8, 10 to 13) to 77 

 (no. 6); galeae (nos. 9 and 11) to 99 (no. 6); laciniae 2 (no. 9) 

 to 166 (no. 34); hypopharynx (nos. 10 to 13) to 216 (no. 39); 

 labial palpi (nos. 10 to 13) to 52 (no. 33) ; paraglossae (common 

 to all except Acrididae) (nos. 8, 9, 11, 46 and 47) to 89 (no. 4); 

 glossae (common to all except Acrididae) (nos. 8, 9, 11, 37 to 

 42, 44 to 47) to 18 (no. 5); ligula (common to only Acrididae) 

 (no. 15) to 56 (no. 24) ; labrum (nos. 8, 9, 10, 12 and 13) to 

 31 (no. 39); mentum (nos. 8 to 13, 37 and 38) to 35 (no. 43); 

 and total number of pores on mouth-parts 30 (no. 11) to 605 

 (no. 43). 



b. Pores on thorax. Relative to the legs and wings of the adult 

 specimens, the number of pores varies as follows: legs 197 (no. 

 11) to 774 (no. 33) ; front wings (nos. 23 and 24) to 134 (no. 33); 

 and hind wings (nos. 8, 9, 39 and 40) to 284 (no. 44). The 

 front wings of nos. 23 and 24 are much reduced, about as long as 

 the abdomen; they have grown together and are rigid like the 

 elytra of beetles. The front wings of nos. 39 and 40 are much 



