208 SUMMARY OF CURRENT RESEARCHES RELATING TO 



common dwelling, according to the feeding requirements of its various 

 inmates. 



Parthenogenesis of Death's-head Moth.* — Sig. C. Massa describes 

 a case of parthenogenetic birth in the Death's-head moth (Spliinx 

 atropos). The insects were isolated in the larval stage, only one survived, 

 a female which laid eggs, a few of which hatched, though none survived. 

 If this is the first time the fact has been noticed in Sphinx atropos an 

 addition must be made to the already long list of occasionally partheno- 

 genetic moths. 



Mouth-organs of two species of Rhysodidse.f — Mr. G. Lewis gives 

 an account of the mouth-organs of Bhysodes niponensis and Clinidium 

 veneficum, which have been dissected out by the Eev. A. Matthews. The 

 gnathites of the latter are exceedingly fragile, while the surrounding 

 integument is almost as hard as iron, and cannot be penetrated without 

 more or less danger to the finer parts. These organs are the most 

 extraordinary that Mr. Matthews has ever seen ; the labrum is very 

 large, the clypeus and mentum very large and of the hardest and most 

 impenetrable horn ; the maxillary palpi are very long, the maxillae, 

 labium, and lingua exceedingly fragile and minute. The labium appears 

 to be extensile, like that of Stenus ; the lingua is very large and broad, 

 and so thin as to be perfectly transparent. The mandibles are abnormal, 

 being inclosed in a horny envelope open on the inside. 



Thysanura and Collembola.| — Dr. J. T. Oudemans has a contribu- 

 tion to our knowledge of these Insects, He finds that the Thysanura 

 present many points of agreement with one another ; all have ten 

 abdominal segments, the last of which carries cerci, and several of those 

 in front have actively moving, laterally placed legs. In the Collembola 

 the number of abdominal segments varies, but is always less than ten ; 

 there are no appendages on the last segment, for the anal hooks cannot 

 be considered as such ; there is a springing apparatus on the median 

 line of the ventral surface. Eyes may or may not be present ; in the 

 former case the Thysanura have compound, but the Collembola merely 

 simple eyes. The body may or may not be covered with scales. The 

 eversible vesicles on the hind-body of MacMlis, Nicoletia, and Campodea 

 have a very similar structure to the eversible parts of the ventral tube 

 of the Collembola. 



The abdominal nervous system of the Thysanura has eight ganglia ; 

 in Campodea there appear to be only seven; the fusion of ganglia 

 seems to be less marked in elongate forms (e.g. Templetoniinse and 

 Lipurinse) than in the compressed Sminthurinte. The eyeless forms 

 appear to have lost their eyes in consequence of their mode of life under 

 stones, in earth, bark of trees, and so on. 



The form of the mouth-parts in the two groups is very similar ; the 

 labium is always deeply cleft, as in the Orthoptera, In the Thysanura 

 the mandibles and maxillae are open internally, and by this orifice the 

 muscles pass which are attached to the outer wall ; it is probable, 

 though not certain, that the same is true of the Collembola. The 

 enteric canal is always straight and never longer than the body ; a mas- 

 ticatory stomach is found in Lepisma only. The epithelium of the 



* Bull. Soc. Entom. Ital., xx. (1888) pp. 64-5. 



t Ann. and Mag. Nat. Hist., ii. (1888) pp. 483-4. 



J bijdrageu tot de Dierkunde, xvi. (1888) pp. 146-226 (3 pis.). 



