1916] Reflex '' Bleeding ' of Epilachna 203 



DISTRIBUTION OF HYPODERMAL GLAND PORES. 



In order to study the distribution of the pores through 

 which the hquid presumably comes, causing the integument to 

 be wet, several specimens were treated with caustic potash 

 twenty-four hours. When removed from the caustic potash, all 

 the tissues were disintegrated leaving only the chitinous parts. 

 When thoroughly washed with water the chitinous integuments 

 were carefully examined. 



Minute pores were observed in the chitin of the thorax, 

 abdomen, legs and elytra. The wings contain none of these 

 pores and the head with its appendages were not examined. 

 A single pore (Figs. 1, 6 and 7, p) usually hes near the base of 

 each hair, but sometimes two pores may be seen near the base 

 of a hair. Sometimes a pore hes against the hair socket (Fig. 

 7, sk). When the pores are more numerous than the hairs, 

 they are grouped together and are not associated with the hairs. 

 The pores are most abundant on the legs (Figs. 1-3, p). Besides 

 most of the hairs on the legs being associated with pores, four 

 groups of this type of pore He near the femoro-tibial articulation 

 and these pores are also grouped together on the tarsal joints. 

 For this reason the region around the femoro-tibial articulation 

 (Fig. 1) contains the most pores of any part of the integument. 

 The first tarsal joint (Fig. 2) contains less and the fourth tarsal 

 joint (Fig. 3) is least well supplied with pores. The thorax 

 (Fig. 6) and the dorsal side of the elytron (Fig. 7) are well 

 supphed with pores, but here the pores are associated with the 

 hairs and are never grouped together. 



Another type of pore was found. While examining the 

 articular membranes (Fig. 1, artm) of the femoro-tibial artic- 

 ulations, many minute pores were seen in them. This is the 

 first time that pores are reported in the articular membrane. 



The group of pores (Fig. 1, a) always present on either side 

 of the proximal end of the tibia is oval in shape and the chitin 

 containing the pores is Hghter in color than the surrounding 

 chitin. In counting the pores in the groups, all the legs of five 

 individuals were used. The number of pores in the groups on 

 the tibse of the front legs varies from 14 to 25 with 17 as an 

 average; on the tibias of the middle legs from 13 to 30 with 20 

 as an average: on the tibiae of the hind legs from IS to 28 with 

 23 as an average. The general average number of pores in 

 these groups for all three pairs of legs is 20. 



