ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 119 



The Louse and Disease.* — B. F. Cummings publishes an account 

 of two species of louse parasitic on man, their life-history and habits, 

 and the best methods of dealing with them. The third species, Phthyrius 

 jnihis, the crab-louse, is merely mentioned. Points of difference 

 between the clothes-louse (Fedicidus humanus) and the head-louse 

 (P. capitis) are : the clothes-louse is larger, the smallest adults being 

 larger than the largest examples of the other species ; it is paler in 

 colour, the body behind the head is broader, and the clefts which run 

 in from the sides are deeper. The "gonopods," minute flap-like 

 appendages at the posterior end of the lower surface of the female, 

 become narrower towards the tip in P. humanus than in P. capitis. In 

 the life-history it is important to note that, though the young louse 

 normally emerges in eight days, temperature and other conditions may 

 retard development, and the egg may hatch five weeks after it has been 

 laid. Various vermicidal substances that have been tried during the 

 war ai'e discussed, and a mixture of naphthalene with 2 p.c. iodoform and 

 2 p.c. creosote (N.C.I.) and " Yermijelli " are recommended. 



Ancestry of Insects.f — J. D. Tothill argues from embryological 

 data and from primitive generalized forms like Stenodictya that winged 

 insects or Pterygogenea are closely related to centipedes (Chilopods), 

 and were possibly derived from an ancient stock in which the 

 maxillipedes were not developed as jaws ; also that the Chilopods were 

 in turn derived (as Handlirsch suggests) from ancient generalized 

 Trilobites. In the Trilobites practically all the segments were added 

 after the egg stage ; in the Chilopods most of the specialization by 

 addition of segments takes place during the egg stages ; in the Hexapods 

 the segments arise only during the Qgg stage. 



Insects of Rice-fields. :|: — F. Supino has studied some of the aquatic 

 insects that are of practical importance in the rice-fields near Milan. 

 He deals particularly with the larvae of Stratiomys chamaeleon (Diptera), 

 Tridenodes bicolor (Neuroptera), and Hydrocampa {Nymphida) nymphseata 

 (Lepidoptera). 



PhoresisJ— E. Roubaud uses this term, suggested in 1896 by 

 Lesne, in reference to the transporting role of some animals. Thus 

 Ateuchus laticollis carries the fly Limosina sacra ; while Scarabseus 

 indicus and S. gangeticus carry Limosina eqnitans. In Equatorial and 

 East Africa Eoubaud has observed some Diptera of the group Borboridse 

 which have " phoretic hosts." Thus Trichocypsela longiseta is found on 

 the coprophagous beetle PachyJomera femoralis Kirby, and T. nasuta on 

 Catharsius lux, a Coprid. In the last case the fly remains attached to 

 the beetle until it enters its burrow with its ball of dung. Then the fly 

 moves off and lays its eggs in the dung, probably returning afterwards 

 to its bearer. Another case described is that of L. pallidicornis Vill. 

 which is borne by an lulid. The fly lays its -eggs in rotting vegetable 



* Brit. Mus. Nat. Hist., Economic Series, No. 2 (1915) 16 pp. (4 figs.). 



t Amer. Journ. Science, xlii. (1916) pp. 373-87 (8 figs.}. 



X Rend. R. 1st. Lombardo, xlix. (1916) pp. 108-14. 



§ Bull. Soc. Zool. France, xli. (1916) pp. 43-5. 



