172 BTR. A. E. CAMERON ON 



11. Structure of the Alimentary Canal of the Stick-Insect, 

 Bacillus rossii Fabr.; with a Note on the Parthenogenesis 

 of this Species. By Alfred E. Cameron, M.A., B.Sc, 

 Fullertoii Scholar of the University of Aberdeen and 

 Research Student in the University of Manchester *. 



[Received October 6, 1911 : Read November 21, 1911.J 



(Plates XXVIII.-XXX.t) 



IntroduGtwyi 



The following description of BaGilhis rossii, a species of the 

 Phasmidpe, is translated from Girard's ' Tvaite Elementaire d'Ento- 

 mologie ' (p. 100) (Paris, 1879). 



" The genus Bacillus is of special interest, as it includes the 

 only species of Phasniid known to occur in Europe ; this is 

 Bacillus rossii Fabr., green, greyish green, or brownish red, with 

 integument either smooth or bearing slight projections, antennae 

 composed of 12 to 23 segments, with a dorsal ridge, with slender 

 legs angularly striated, the anterior pair very long, the two 

 posterior pairs of femora tridentate below. The male is from 

 45 to 55 mm-, long, the female from 58 to 108 mm, The species 

 is native to South Europe and North Africa, and was discovered 

 by Rossi in the gardens and heaths of Tuscany ; it is common on 

 the green hedgerows bordering water-filled ditches ; it is found 

 also in Dalmatia and in Istriai Near the town of Pola this 

 motionless Phasmid occurs on the Montpellier rock-rose ; but so 

 great is its resemblance to the twigs among which it lives that it 

 is very difficult of recognition ; its enemies, besides parasitic 

 larvae, are the Praying Mantis and the Green Lizard. A smaller 

 race of Bucillus ix)ssii exists with antennae of 12 segments, thorax 

 bearing minute prominences, the female 54 to 67 mm. in length, 

 of which several authors make a distinct species under the name 

 of B. gallictos Charp., B. granulaUis Brulle, found in Greece at 

 the time of the French expedition, also in Andalusia (Rambur), 

 in North Africa^ in the South-East and South-West of France, 

 at Nice, at Cannes, at Hyeres, near Toulon. In the early spring 

 the insects may be captured by shaking the bushes over an open 

 umbi^Ua, when there fall into it both adults which have hiber- 

 nated and larvae in various stages of development ; the larvae 

 being more delicate than the adults preserve badly when collected, 

 becoming twisted and folded* The species is said to be found in 

 isolated examples as far north as Orleans. 



" B. rossii is found in Algeria, in places which afe covered with 

 grasses and shaded from the light. 



" The genus includes one-fortieth of the species of Phasmidae of 



* Communicated by Professor Sydney J. Hicksok, F.E.S., F.Z.S. 

 t For explanation of the Plates see p. 182. 



