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TEXT-BOOK OF ENTOMOLOGY 



descendant of a group of myriopods from which the Campodeae, 

 Thysanura, and Collembola may have sprung." We are indebted 

 to Grassi for the first extended work on the morphology of Scolo- 

 pendrella (1885). In 1886 he added to our knowledge facts 

 regarding the internal anatomy, and gives a detailed comparison 

 with the Thysanura, besides pointing out the resemblances of Scolo- 

 pendrella to Pauropus, diplopods, chilopods, as well as Peripatus. 



In 1888 Grassi expressed his view as to the position of the 

 Symphyla, stating that it should not be included in the Thysanura, 

 since it evidently has myriopod characters; these being the supra- 

 spinal vessel, the ventral position of the genital glands; the situa- 

 tion of the genital opening in the fourth segment of the trunk, its 

 ganglionic chain being like that of diplopods, its having limbs on 

 all the segments, etc. On the other hand, Grassi has with much 

 detail indicated the points of resemblance to the Thysanura. The 

 principal ones are the thin integument, the want of sympathetic 



st oe:v 



FIG. 15. Section of ScoIopendreJla imm<tcnJ(tf(i : ?, oesophagus; oe. v, ossophageal valve 

 entering the mid intestine ("stomach") ; i, intestine ; r, rectum ; br, brain ; *, abdominal chain 

 of ganglia : <,/</, oviduct ; or, ovary ; *. !?', silk-gland, and op, its outer opening in cercus , w. t, uri- 

 nary tube ; eg, coxal glands or blood-gills. Author del. 



ganglia, the presence of a pair of cephalic stigmata, like that said 

 to occur in certain Collembola, and in the embryo of Apis; two 

 endoskeletal processes situated near the ventral fascia of the head ; 

 the epicranial suture also occurring in Thysanura, Collembola, 

 Orthoptera, and other winged insects, and being absent in diplopods 

 and chilopods. He also adds that the digestive canal both in 

 Symphyla and Thysanura is divided into three portions; the mal- 

 pighian tubes in Thysanura present very different conditions (there 

 being none in Japyx), among which may be comprised those of 

 Scolopendrella. In both groups there is a single pair of salivary 

 glands. The cellular epithelium of the mid-intestine of Scolopen- 

 drella is of a single form as in Campodea and Japyx. The fat- 

 body, dorsal vessel, with its valves and ostia, are alike in the two 

 groups, as are the appendages of the end of the abdomen, the anal 

 cerci (cercopoda) of Scolopendrella being the homologues of the 



