420 ME. H. M. BEEDSTAED ON THE CHEENETID^. 



probably be true silk-giands. It is wortb. recording, bowever, 

 tbat tbe same kind o£ openings have been claimed for tliese 

 abdominal glands in the Chernetidse. 



The anterior j)apilla opens into a short duct, into which, 

 laterally and dorsally, groups of large pyriform glands pour their 

 secretions. These glands are so crowded together that the 

 secreting epithelium can properly develop only at their proximal 

 ends, where the cavity is very deep, the cells in section being 

 polygonal owing to mutual pressure (fig. 11). 



The posterior papilla leads into a tuberous gland, the exact 

 nature of which it is not easy to make out. The epithelium is 

 like that of the pyriform glands, but the lumen looks like a 

 shrunken chitinous sac (figs. 10, 11, 12). 



These glands were developed only in one of the specimens at 

 my disposal (figs. 10, 11). In the other three specimens, traces 

 of them were visible in one ; in a second the part was unfor- 

 tunately torn away from the sections ; while in the third there 

 was no trace of them whatever. Evidently, therefore, these 

 glands are, like the true spinning-glands, liable to periodic 

 variations. I may further remark that the only specimen which 

 shows these abdominal glands is the specimen which shows no 

 trace of the true spinning-glands. It is true that my sections 

 are here somewhat broken, but I do not doubt that this is the 

 case. If so, we have here an interesting relation between the 

 spinning-glands and the abdominal glands. 



The presence of true spinning -glands on the mandibles, with 

 their manipulating combs, seems to indicate that these abdominal 

 glands are not the producers of the silk for the nest, though the 

 secretion itself in these latter may be somewhat of the same 

 nature as in the former ; the largeness of the single apertures 

 shows that they have nothing to do with the spinning of silk. 

 On the other hand, the opening of the more important of the 

 abdominal glands under the genital operculum would imply 

 some connection with reproduction. Croneberg calls them 

 " Kittdrlisen " (cement-glands). The function of these cement- 

 glands is perhaps that of sticking the eggs to the abdominal 

 surface of the mother, as there are several notices in literature 

 that these animals carry about the eggs firmly attached to the 

 ventral surface of the anterior abdominal segments. If this is 

 the case, then it appears as if the male shared with the female 

 the discharge of this function, because from the occurrence of the 



