August 24, 19 16] 



NATURE 



529 



tion of the extraordinary deep-sea genus Hexacrobylus, 

 hitherto known but imperfectly Ironi a single speci- 

 man discovered by the Stboga expedition, but now 

 elucidated by five well-preserved specimens dredged 

 by the Investigator from 1912 fathoms off Ceylon. 

 In Hexacrobylus indicus, which the author regards as 

 an aberrant Molgulid, the body is ovate and covered 

 with delicate hairs ; the branchial aperture is a wide 

 transverse slit, ventral in position, and surrounded by 

 six many-lobed tentacles, which collectively resemble 

 thick, prominent, warty lips ; the branchial siphon is 

 nearly as large as the trunk itself; the branchial sac 

 is scarcely distinguishable from the oesophagus, and is. 

 imperforate ana destitute of stigmata, endostyle, and 

 dorsal lamina; the gonads are symmetrically developed 

 on both sides of the body, and the ovaries and testes 

 have separate ducts : though differing from the 

 Siboga species, it agrees with it in those features 

 which separate it so widely from all other Ascidians. 

 Another interesting new genus is Monobotryllus, 

 which, though a simple Ascidian, is most closely 

 related to some of the holosomatous compound 

 Ascidians. 



Colonel Stephenson's paper, which treats of Oligb- 

 chseta collected mainly in southern India and Ceylon, 

 though largely anatomical and systematic, is digni- 

 fied by much instructive comparison and criticism. 

 Twentv species and five varieties are described as new, 

 among them a Pontodrilus from Ceylon remark- 

 able in its habitat, far from the sea, at an elevation 

 of 6200 to 7000 ft. Two new genera are defined, 

 namely, Erythraeodrilus from Bombay, apparently 

 related to the Madagascar Howascolex ; and Comaro- 

 drilus a Megascolecine from Cochin, in alliance with 

 Woodw'ardia. 



Part vi. of vol. xi. of the Records contains three 

 papers of more than common interest. Dr. James 

 Ritchie gives an exhaustive description of Annulelta 

 gemmata, a remarkable new Hydroid discovered by 

 Dr. Annandale in a brackish pond at Port Canning 

 in the Gangetic Delta. It is a minute form, solitary 

 and usually attached, but also freely locomotive. Its 

 attachment is by a " basal bulb," which alone is in- 

 vested bv perisarc, and is regarded as something 

 between a basal disc and a hydrorhiza. Its tentacles, 

 which are of extreme length, have the cnidoblasts 

 concentrated in whorl-like rings, the cnidoblasts being 

 almost identical with those of Hydra. The usual 

 methods of propagation seem to be non-sexual, but 

 Dr. .Annandale, who kept specimens alive, states that 

 minute medusae are liberated. The non-sexual 

 methods include longitudinal fission, transverse fission 

 of the basal bulb, and the detachment of remarkable 

 planula-like buds. 



Dr. Annandale contributes an account, biological 

 and systematic, of sponges parasitic on Indian Clionid 

 sponges. Ten such parasites are reviewed, along 

 with five Clionid hosts, the greater part of the col- 

 lection being furnished by a few ounces of Madre- 

 porarian coral. The methods of attack and defence 

 are discussed very fully. Among assumed methods of 

 protection observed in certain Clionids inhabiting 

 great depths, where the inorganic conditions of life 

 may reasonably be supposed to be constant, is the 

 production of gemmules. 



Mr. F. H. Graveley's copious and well-ordered 

 notes on the habits of insects and other Arthropods 

 must be greatly commended. In addition to record- 

 ing many original observations of behaviour, court- 

 ship, breeding, etc., particularly of that retiring group 

 the Pedipalpi, the author has extracted references 

 ', to multifarious observations published, mainly in 

 ! Indian journals and in books relating to India, by 

 ' other writers. 



NO. 2443, VOL. 97] 



RECENT ECONOMIC ENTOMOLOGY. 



THE economic importance of the Coccidae (' mealy 

 bugs " and scale-insects) is verj' great, especially 

 in warm countries. It is satisfactory to see, therefore, 

 the first part of an extensive monograph on the Cocc- 

 idae of South Africa, by C. K. bram, published as 

 part 2 of vol. V. of the Transactions Royal Soc. S. 

 Africa (Cape Town, 1915). This contains a general 

 introduction to the study of the family and detailed 

 descriptions of the genera and species of the Pseudo- 

 coccinae, Ortheziinae, Coccinae, Monophlebinae, and 

 Margarodinae. The systematic work has been done 

 witii great care, a notable feature being the charts 

 demonstrating in the case of each species the range 

 of variation in the lengths of the antennal segments ; 

 the illustrations — photographs and drawings — fill 

 thirteen plates. The author has spared no pains to 

 enlighten his readers, but it was scarcely necessary 

 to include in his glossary the information that " ovum " 

 means " an egg," and "" transparent," " so clear as not 

 to obstruct vision." 



The Bulletin of Entomological Research, vol. vi., 

 part 4, lately issued, contains, as usual, several note- 

 worthy papers. Prof. G. H. F. Nuttall and Mr. C. 

 Warburton describe briefly, with clear illustrations, 

 thirty species of ticks from the Belgian Congo, and 

 point out the importance of each as a carrier of disease. 

 Mr. C. H. T. Townsend, of the U.S. Department of 

 Agriculture, establishes — in reply to some recent scep- 

 tical criticism — that Phlebotomus is truly the infec- 

 tive carrier of the Verruga parasite. Dr. G. A. K. 

 Marshall describes, with excellent figures, some weevils 

 injurious to various cultivated plants in India. The 

 highly useful Review of Applied Entomology has just 

 commenced its fourth volume, and the first summary 

 in the medical and veterinary- series directs attention 

 to the existence of the British and Irish sheep-fly 

 {Lucilia sericata) as a pest in the southern United 

 States, together with Phormia regina, on the authority 

 of Messrs. F. C. Bishopp and E. \V. Loake, in a 

 paper published in the Journ. Econ. Entotn., vol. viii., 

 No. 5. 



Literature on the common house-fly continues to 

 accumulate rapidly. Mr. R. H. Hutchinson (U.S. 

 Dept. Agric, Bull. 345) contributes same interesting 

 observations on the " Pre-oviposition Period " of the 

 insect, with a view of estimating the value of fly-traps 

 for reducing the numbers of eggs and larvae. He finds 

 that the term of the female's life before egg-laying 

 varies from 2^ to 23 days, " most of the records falling 

 on the fourth, fifth, sixth, ninth, twelfth, and 'four- 

 teenth days after emergence." 



The larval trombidiid mites known as " harvest 

 bugs " are too familiar as a well-nigh intolerable 

 pest in some localities. Mr. Stanley Hirst (Journ. 

 Econ. Biol., vol. x., No. 4) gives a careful description 

 of this larva under the name of Microtrombidium 

 autumnalis. He also describes a Japanese species, 

 M. akamushi , which carries the germ of a disease 

 known as '"river fever." 



In a Technical Bulletin (No. 21) of the Michigan 

 Agricultural College Exf>eriment Station, Mr. Geo. D. 

 Shafer continues the account of his investigations as 

 to how "contact poisons" kill insects. Such gases as 

 sulphuretted hydrogen, hydrocyanic acid, and the 

 vapours of carlxjn disulphide, benzine, or paraffin affect 

 insects when actually taken up by the tissues, where 

 their presence seems to prevent oxygen assimilation. 

 This result is due to the harmful effect of such gases 

 and vapxjurs on the enzyme-like bodies — reductases, 

 catalases, and oxydases — which are functional in insect 

 tissues. The contact poisons are believed to affect the 

 activities of these enzymes to an unequal degree, thus 

 disturbing their normal balance. 



