852 . MB, W. BATESOK ON THE [DeC. 3, 



colour, it is necessary first to sort them in respect of sex. This 

 can be clone without much difficulty. Besides a slight difference 

 in shape and in sculpture (which gives to the elytra of the female 

 a duller lustre) there is a well-marked depression or pit in the last 

 uncovered abdominal plate of the male, while in the female there 

 is no such depression. 



In attempting to arrange or group the specimens according to 

 colour confusion is caused by the fact that variation occurs in 

 several distinct features. Of these the three most noticeable are : 



(1) The ground-colour of the elytra. 



(2) The distribution of black pigment on the elytra. 



(3) The colour of the legs and underside of the body. 



Since the variations of the first two points are largely inde- 

 pendent, it is not possible to exhibit the relationships and fre- 

 quencies of all the variations by arranging the specimens in one 

 series. The whole number, males and females, can, however, be 

 seen to consist of two chief kinds — the one distinguished by having 

 four Mack spots on the elytra (figs. 1-6, &.c.) and a dark, generally 

 black, underside to the body, while the other has an appearance 

 of hlack striping on the elytra (figs. 20-23) associated \\it\i a light 

 testaceous underside to the body. Those with undersides that 

 cannot at once be referred to either the dark or to the light 

 division are rare ; in the Tables given they are included under 

 the heading " unconformable." In those with light undersides the 

 legs are of a similar testaceous colour. If the underside is black, 

 the femora are generally black too ; but frequently the coxse and 

 tarsi, and less often the tibiae, are of a lighter colour. 



Examined closely the distinction between the distribution of the 

 spots and the stripes is seen to be as follows :• — The striping 

 consists of pigment deposited in certain positions that can be 

 defined pretty accurately by reference to the punctulations. These 

 are somewhat more regularly disposed in the female than in the 

 male, but by standing back to the light and looking at the 

 specimen from behind it can be seen that the following arrange- 

 ment is fairly constant. Following a line across the middle of an 

 elytron there is next to the suture a double row of punctulations. 

 External to this is an interval. Then come the 2ud-8th double 

 rows of punctulations separated by intervals. Outside the eighth 

 interval is a 9th row of punctulations, which is irregularly treble. 



It is in the four intervals between the 2nd and 3rd, 4th and 5th, 

 6th and 7th, 8th and 9th double rows that the four chief tracheae 

 of the elytron run ; but the four principal stripes of pigment 

 are placed in the other intervals, viz., between the 1st and 2nd, 

 3rd and 4th, 5th and 6th, 7th and 8th double rows of punctu- 

 lations. There are not rarely a few dots of pigment in the other 

 intervals, and, in the case of heavily striped specimens, these some- 

 times unite to form secondary stripes. 



The definite " spots," however, that are associated with the 



