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Cybister Deegener describes a second temporary epithelium, 

 found late in larval life, and inserted between the old larval 

 and temporary pupal epithelia. It should be noted that the 

 temporary pupal epithelium is a very transient structure, and 

 that its absence in some insects is only apparent. 



In Galeruca Poyarkoff described a very interesting 

 rejuvenation in the cells of the fore- and hindguts, similar 

 to that occurring in the integument. In the silkworm, 

 according to Verson, and also probably in the Coleoptera, 

 there is a cell proliferation in the epithelium of the fore- and 

 hindguts previous to each larval moult. This is evidently 

 comparable with the proliferation of the fat cells of Galeruca 

 as observed by Poyarkoff. Its significance will be explained 

 in the eecond portion of this paper. 



The malpighian tubes are of special interest. In Nasonia, ' 

 and evidently in many other chalcid wasps, they are absent 

 in the larva. In CalUphora Lowne believed them to undergo 

 phagocytic destruction ; but more recently Perez has observed 

 them to undergo during pupation a remarkable process of 

 dedifferentiation, followed later by redifferentiation into 

 imagihal organs. In Galeruca, however, there is a phago- 

 cytosis of old larval elements, accompanied by a development 

 of embryonic cells to form the imaginal organs. 



THE DUCTLESS GLANDS. 

 Under this heading three structures will be considered : — 

 (a) The oenocytes; (b) a pair of lateral intestinal glands, 

 occurring only in the larva, and which have not, I believe, 

 hitherto been observed; and (c) a pair of dorsal abdominal 

 glands, functional only in the adult insect, and also, so far 

 as I am aware, hitherto unrecorded. 



The Oenocytes. 

 The term oenocyte was first applied by Wielowiejsky in 

 1886 to certain very large cells scattered about among the 

 cells of the fat-body of Corethra. Tichomiroff had already 

 noticed then in 1882 in the silkworm; he observed their 

 proximity to the tracheae and regarded them as of ectodermal 

 origin. Wheeler in 1892 found them to delaminate from the 

 ectoderm; Weissenberg in 1907, studying them in a chalcid 

 wasp Torymus, came to a similar conclusion. Finally, Nelson 

 (1915), examining them in the embryo of the honey bee, saw 

 them invaginating in close relation with the stigmatic trunks 

 from the lateral ectoderm. Berlese has described them in 

 the hymenopteran Tapinoma as a pair of small masses of 

 cells in the fifth to the eleventh segments. 



\y 



