538 SUMMARY OF CURRENT RESEARCHES RELATING TO 



tissue caught between them. The two saws are strengthened, lattice- 

 girder fashion, by transverse thickenings on their outer surfaces, which 

 are thus uneven and irregular, but their opposed faces are quite flat, and 

 slide smoothly on one another. 



Bird-lice of British Auks.* — James Waterston gives an account 

 of five species of Docophorus found on razorbills, guillemots, little auks, 

 and puffins. They fall into two sets : (a) D. acutipectus, D. calvus, and 

 D. celedoxus ; and (b) D. megcuephalus and D. merguli'. About fifty 

 specimens is regarded as about the normal number to be expected on 

 one host, but taking the concomitant Nirmus and Menopon into the 

 reckoning, 100-120 may not be an excessive estimate of the mallo- 

 phagous parasites of a bird before the moult. Each of the five auks in 

 British waters has a species of Docophorus peculiar to itself within that 

 area, but "straggling" of an interesting kind is also exhibited. 



Monograph of Jumping Plant-lice of the New World.f — David L. 

 Crawford has accomplished the task of taking a survey of the Jumping 

 Plant-lice or Psyllidae of the New World. A complete re-arrangement 

 of the genera is presented, based on the form of the head, the vertex, 

 the pleurites of the prothorax and of the pronotum, the armature of 

 the hind tibiae, the venation of the wings, and so on. Six sub-families 

 are recognized : Liviinee, Pauropsyllinas, Carsidarinas, Ceriacreininas, 

 Triozinas, and Psyllinas. Numerous new forms are described. The 

 Psyllids are usually very active little creatures, with an interesting 

 combination of leaping and flying. When disturbed a Psyllid throws 

 itself into the air by means of its powerful hind legs, which are doubled - 

 up like a letter Z with a short base. Once in the air it vibrates its 

 wings and thus increases the rapidity of its leap and the distance covered. 

 The wings are scarcely strong enough to permit of rapid or prolonged 

 flight unaided by the preliminary leap. By this combined leaping and 

 flying, however, the insect is able to travel several yards, although more 

 often it merely leaps a few inches or feet from the point of disturbance. 



Saws of Female Dolerids.J— F. 1). Morice continues his work on 

 the terebras of this difficult group by publishing a beautiful series _ of 

 photographs, thirty-six in all, showing specific differences not in outline 

 alone, but in surface, especially as regards the remarkable alternating 

 elevations and depressions. He believes that, taking them as a whole, 

 and considering all their characters, the saws he figures can be divided 

 into more or less definite groups, and that these groups to some extent, 

 but not altogether, correspond to sub-divisions already pointed out by 

 various authors — subdivisions founded on external characters only, and 

 without any consideration of the structure of the saw. These groups 

 are discussed in detail. 



* Proc. E, Phys. Soc. Edinburgh, xix. (1914) pp. 149-58. 



t Smithsonian Inst. U.S. Nat. Museum, Bull. 85 (1914) ix and 186 pp. (30 pis.). 



X Trans. Ent. Soc. London, 1913, pp. 428-35 (3 pis.). 



