THE OLFACTORY SENSE OF COLEOPTERA. 415 



are close together and are not scattered as they are in the other 

 four species (Nos. 2, 34, 35, 44). In some beetles it is almost 

 impossible to identify the various chitinous plates in the peduncles 

 of the elytra, but as far as can be ascertained the definite groups 

 of pores are located on the radial plates, while the scattered 

 groups may spread over two or more of the plates. In shape 

 these groups are round, oblong and triangular. The triangular- 

 shaped ones are most common. As a rule, the more pores in this 

 group, the smaller they are and the closer they are together. 

 In three species (Nos. 23, 29, 36) the pores in this group are com- 

 paratively large, while those in the lady beetles are medium in 

 size. Osmiis with 12 pores on both elytra has the least number 

 and Hydrophilus with 310 pores on both elytra has the largest 

 number. In regard to the total numbers of pores on the elytra 

 for the 50 species, the reader is referred to the table on page 

 419. 



The three beetles, Osmus, Clinidium and Cysteodemus, are 

 wingless. No rudiments of the wings were even found. The 

 number of groups of pores on each wing of the other species 

 varies from i to 4. Ten species (Nos. i, 10, 13, 14, 16, 17, 18, 

 21, 22, 47) have only one group on each wing. One wing of 

 Lucidota has one group while the other wing has two groups. 

 Twenty-one species (Nos. 4, 5, 8, ii, 20, 24, 25, 26, 28, 30, 31, 

 32, 36, 38, 40, 42, 43, 45, 46, 49, 50) have two groups on each 

 wing. Twelve species (Nos. 3, 6, 7, 9, 15, 23, 29, 33, 37, 39, 41, 

 48) have three groups on each wing. Three species (Nos. 12, 34, 

 35) have four groups on each wing. When only one group is 

 present on each wing it usually occupies the position of Nos. 3 

 and 4 of Epilachna borealis on the radius (Text-fig. iC). It may 

 be no longer than No. 4 of Epilachna, or it may extend nearly 

 all the distance to the fold of the wing {Fo). When two groups 

 are present on each wing, one is similar to No. 2 of Epilachna 

 and the other is similar to Nos. 3 and 4 united. The latter 

 group may or may not extend all the way to the fold of the wing. 

 In Collops, 20 pores were found on the ventral side of one wing 

 besides the two groups on the dorsal surface. When three 

 groups are found on each wing, they may be located like those of 

 Epilachna, or two of them may lie on the radius and the third 



