204 Annals Entomological Society of America [Vol. IX, 



The group of pores (Fig. 1, 6) at the distal end of the femur 

 and near the articular membrane is arranged in a manner more 

 or less like a string of beads (Fig. 4). A group is present on 

 either side of the articular membrane, but both groups on the 

 same femur can never be seen because one of them always lies 

 under a portion of the femur. For this reason the pores in 

 only about a half of these groups were counted. On the front 

 legs the pores vary from 24 to 26 with 25 as an average ; on the 

 middle legs from 24 to 37 with 30 as an average; on the hind 

 legs from 29 to 38 with 32 as an average. The general average 

 number of pores in the groups on the femurs of all three pairs 

 of legs is 30. 



On account of the opaqueness of the articular membrane 

 and the small size of the pores found in this membrane, these 

 pores can not be counted, but they are estimated as from 200 

 to 500 for each membrane 



Since the four groups. of pores near the articular membrane 

 and those in the membrane are the only openings, besides a few 

 olfactory pores (Fig. 1, olp) and the pores associated with the 

 hairs, which pass through the chitin at the femoro-tibial artic- 

 ulation where the drop of liquid appears, we must conclude 

 that these pores are the only passages through which the liquid 

 is ejected to the exterior. Counting only the pores in these 

 groups and those in the articular membrane, we see that each 

 tibia has 40 pores, each femur 60 pores, and each articular 

 membrane perhaps 400 pores, making about 500 pores through 

 which the liquid issues. Since all of these pores are so close 

 together the liquid from all of them unites into a drop, while a 

 drop is never seen elsewhere except on the first tarsal joint 

 where there are also many pores near one another. 



STRUCTURE. 



In the preceding pages it is shown that the liquid ejected 

 passes through pores in and near the articular membrane. In 

 the following pages it shall be determined whether the liquid 

 ejected is blood or a glandular secretion. 



1. External structure. 



When observed under a high-power lens, the pores in the 

 groups and those associated with the hairs appear as very small 

 light spots. In a vertical view each light spot (Fig. 3, p) is 



